{"trustable":false,"prependHtml":"\u003cstyle type\u003d\u0027text/css\u0027\u003e\n .input, .output {\n border: 1px solid #888888;\n }\n .output {\n margin-bottom: 1em;\n position: relative;\n top: -1px;\n }\n .output pre, .input pre {\n background-color: #EFEFEF;\n line-height: 1.25em;\n margin: 0;\n padding: 0.25em;\n }\n \u003c/style\u003e\n \u003clink rel\u003d\"stylesheet\" href\u003d\"//codeforces.org/s/96598/css/problem-statement.css\" type\u003d\"text/css\" /\u003e\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cp\u003e Fox Ciel is going to publish a paper on FOCS (Foxes Operated Computer Systems, pronounce: \"Fox\"). She heard a rumor: the authors list on the paper is always sorted in the \u003cspan\u003elexicographical\u003c/span\u003e order.\u003c/p\u003e \n \u003cp\u003e After checking some examples, she found out that sometimes it wasn\u0027t true. On some papers authors\u0027 names weren\u0027t sorted in \u003cspan\u003elexicographical\u003c/span\u003e order in normal sense. But it was always true that after some modification of the order of letters in alphabet, the order of authors becomes \u003cspan\u003elexicographical\u003c/span\u003e!\u003c/p\u003e \n \u003cp\u003e She wants to know, if there exists an order of letters in Latin alphabet such that the names on the paper she is submitting are following in the \u003cspan\u003elexicographical\u003c/span\u003e order. If so, you should find out any such order.\u003c/p\u003e \n \u003cp\u003e \u003cspan\u003eLexicographical\u003c/span\u003e order is defined in following way. When we compare \u003cspan\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e and \u003cspan\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e, first we find the leftmost position with differing characters: \u003cspan\u003e\u003ci\u003es\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e ≠ \u003ci\u003et\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e. If there is no such position (i. e. \u003cspan\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e is a prefix of \u003cspan\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e or vice versa) the shortest string is less. Otherwise, we compare characters \u003cspan\u003e\u003ci\u003es\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e and \u003cspan\u003e\u003ci\u003et\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e according to their order in alphabet.\u003c/p\u003e \n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cp\u003e The first line contains an integer \u003cspan\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e (\u003cspan\u003e1 ≤ \u003ci\u003en\u003c/i\u003e ≤ 100\u003c/span\u003e): number of names.\u003c/p\u003e \n \u003cp\u003e Each of the following \u003cspan\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e lines contain one string \u003cspan\u003e\u003ci\u003ename\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e\u003c/span\u003e (\u003cspan\u003e1 ≤ |\u003ci\u003ename\u003c/i\u003e\u003csub\u003e\u003ci\u003ei\u003c/i\u003e\u003c/sub\u003e| ≤ 100\u003c/span\u003e), the \u003cspan\u003e\u003ci\u003ei\u003c/i\u003e\u003c/span\u003e-th name. Each name contains only lowercase Latin letters. All names are different.\u003c/p\u003e \n \u003c/div\u003e \n\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cp\u003e If there exists such order of letters that the given names are sorted lexicographically, output any such order as a permutation of characters \u0027a\u0027–\u0027z\u0027 (i. e. first output the first letter of the modified alphabet, then the second, and so on).\u003c/p\u003e \n \u003cp\u003e Otherwise output a single word \"Impossible\" (without quotes).\u003c/p\u003e \n \u003c/div\u003e \n\u003c/div\u003e"}},{"title":"Example","value":{"format":"HTML","content":"\u003cdiv\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Input\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\t3\r\nrivest\r\nshamir\r\nadleman\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Output\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\tbcdefghijklmnopqrsatuvwxyz\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Input\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\t10\r\ntourist\r\npetr\r\nwjmzbmr\r\nyeputons\r\nvepifanov\r\nscottwu\r\noooooooooooooooo\r\nsubscriber\r\nrowdark\r\ntankengineer\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Output\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\tImpossible\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Input\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\t10\r\npetr\r\negor\r\nendagorion\r\nfeferivan\r\nilovetanyaromanova\r\nkostka\r\ndmitriyh\r\nmaratsnowbear\r\nbredorjaguarturnik\r\ncgyforever\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Output\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\taghjlnopefikdmbcqrstuvwxyz\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Input\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\t7\r\ncar\r\ncare\r\ncareful\r\ncarefully\r\nbecarefuldontforgetsomething\r\notherwiseyouwillbehacked\r\ngoodluck\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003cdiv\u003e \n \u003cdiv\u003e\n Output\n \u003c/div\u003e \n \u003cpre\u003e\r\n\t\t\t\tacbdefhijklmnogpqrstuvwxyz\r\n\u003c/pre\u003e \n \u003c/div\u003e \n \u003c/div\u003e \n \u003c/div\u003e \n\u003c/div\u003e"}}]}