{"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":"MD","content":"![QQ图片20190818231050.png](https://i.loli.net/2019/08/18/xERgdKN824T7Vwj.png)"}},{"title":"Input","value":{"format":"MD","content":"\u003cp\u003eThe first line of input contains two space separated integers \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e and \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003ek\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ \u003ci\u003en\u003c/i\u003e, \u003ci\u003ek\u003c/i\u003e ≤ 100 000\u003c/span\u003e)\u0026nbsp;— the length of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e and the required length of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eThe second line of input contains the string \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e consisting of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003en\u003c/i\u003e\u003c/span\u003e lowercase English letters.\u003c/p\u003e"}},{"title":"Output","value":{"format":"MD","content":"\u003cp\u003eOutput the string \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e conforming to the requirements above.\u003c/p\u003e\n\u003cp\u003eIt\u0027s guaranteed that the answer exists.\u003c/p\u003e"}},{"title":"Examples","value":{"format":"MD","content":"\u003cdiv class\u003d\"sample-test\"\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e3 3\u003cbr\u003eabc\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003eaca\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e3 2\u003cbr\u003eabc\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003eac\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e3 3\u003cbr\u003eayy\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003eyaa\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"input\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e\n \u003cpre\u003e2 3\u003cbr\u003eba\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n \u003cdiv class\u003d\"output\"\u003e\n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e\n \u003cpre\u003ebaa\u003cbr\u003e\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}},{"title":"Note","value":{"format":"MD","content":"\u003cp\u003eIn the first example the list of strings \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e of length 3, such that the set of letters of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003et\u003c/i\u003e\u003c/span\u003e is a subset of letters of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e is as follows: \u003cspan class\u003d\"tex-font-style-tt\"\u003eaaa\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eaab\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eaac\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eaba\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eabb\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eabc\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eaca\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eacb\u003c/span\u003e, \u003cspan class\u003d\"tex-span\"\u003e...\u003c/span\u003e. Among them, those are lexicographically greater than \u003cspan class\u003d\"tex-font-style-tt\"\u003eabc\u003c/span\u003e: \u003cspan class\u003d\"tex-font-style-tt\"\u003eaca\u003c/span\u003e, \u003cspan class\u003d\"tex-font-style-tt\"\u003eacb\u003c/span\u003e, \u003cspan class\u003d\"tex-span\"\u003e...\u003c/span\u003e. Out of those the lexicographically smallest is \u003cspan class\u003d\"tex-font-style-tt\"\u003eaca\u003c/span\u003e.\u003c/p\u003e"}}]}