{"trustable":true,"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":"\u003cp\u003eMr. Kitayuta has kindly given you a string \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e consisting of lowercase English letters. You are asked to insert exactly one lowercase English letter into \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e to make it a palindrome. A \u003cspan class\u003d\"tex-font-style-it\"\u003epalindrome\u003c/span\u003e is a string that reads the same forward and backward. For example, \"\u003cspan class\u003d\"tex-font-style-tt\"\u003enoon\u003c/span\u003e\", \"\u003cspan class\u003d\"tex-font-style-tt\"\u003etestset\u003c/span\u003e\" and \"\u003cspan class\u003d\"tex-font-style-tt\"\u003ea\u003c/span\u003e\" are all palindromes, while \"\u003cspan class\u003d\"tex-font-style-tt\"\u003etest\u003c/span\u003e\" and \"\u003cspan class\u003d\"tex-font-style-tt\"\u003ekitayuta\u003c/span\u003e\" are not.\u003c/p\u003e\u003cp\u003eYou can choose any lowercase English letter, and insert it to any position of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e, possibly to the beginning or the end of \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e. You have to insert a letter even if the given string is already a palindrome.\u003c/p\u003e\u003cp\u003eIf it is possible to insert one lowercase English letter into \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e so that the resulting string will be a palindrome, print the string after the insertion. Otherwise, print \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eNA\u003c/span\u003e\" (without quotes, case-sensitive). In case there is more than one palindrome that can be obtained, you are allowed to print any of them.\u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cp\u003eThe only line of the input contains a string \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e (\u003cspan class\u003d\"tex-span\"\u003e1 ≤ |\u003ci\u003es\u003c/i\u003e| ≤ 10\u003c/span\u003e). Each character in \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e is a lowercase English letter.\u003c/p\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003eIf it is possible to turn \u003cspan class\u003d\"tex-span\"\u003e\u003ci\u003es\u003c/i\u003e\u003c/span\u003e into a palindrome by inserting one lowercase English letter, print the resulting string in a single line. Otherwise, print \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eNA\u003c/span\u003e\" (without quotes, case-sensitive). In case there is more than one solution, any of them will be accepted. \u003c/p\u003e"}},{"title":"Examples","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003erevive\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003ereviver\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003eee\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eeye\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003ekitayuta\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eNA\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Note","value":{"format":"HTML","content":"\u003cp\u003eFor the first sample, insert \u0027\u003cspan class\u003d\"tex-font-style-tt\"\u003er\u003c/span\u003e\u0027 to the end of \"\u003cspan class\u003d\"tex-font-style-tt\"\u003erevive\u003c/span\u003e\" to obtain a palindrome \"\u003cspan class\u003d\"tex-font-style-tt\"\u003ereviver\u003c/span\u003e\".\u003c/p\u003e\u003cp\u003eFor the second sample, there is more than one solution. For example, \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eeve\u003c/span\u003e\" will also be accepted.\u003c/p\u003e\u003cp\u003eFor the third sample, it is not possible to turn \"\u003cspan class\u003d\"tex-font-style-tt\"\u003ekitayuta\u003c/span\u003e\" into a palindrome by just inserting one letter.\u003c/p\u003e"}}]}