{"raw_statement":[{"iden":"statement","content":"Two-gram is an ordered pair (i.e. string of length two) of capital Latin letters. For example, \"_AZ_\", \"_AA_\", \"_ZA_\" — three distinct two-grams.\n\nYou are given a string $s$ consisting of $n$ capital Latin letters. Your task is to find **any** two-gram contained in the given string **as a substring** (i.e. two consecutive characters of the string) maximal number of times. For example, for string $s$ = \"_BBAABBBA_\" the answer is two-gram \"_BB_\", which contained in $s$ three times. In other words, find any most frequent two-gram.\n\nNote that occurrences of the two-gram can overlap with each other."},{"iden":"input","content":"The first line of the input contains integer number $n$ ($2 \\le n \\le 100$) — the length of string $s$. The second line of the input contains the string $s$ consisting of $n$ capital Latin letters."},{"iden":"output","content":"Print the only line containing exactly two capital Latin letters — **any** two-gram contained in the given string $s$ **as a substring** (i.e. two consecutive characters of the string) maximal number of times."},{"iden":"examples","content":"Input\n\n7\nABACABA\n\nOutput\n\nAB\n\nInput\n\n5\nZZZAA\n\nOutput\n\nZZ"},{"iden":"note","content":"In the first example \"_BA_\" is also valid answer.\n\nIn the second example the only two-gram \"_ZZ_\" can be printed because it contained in the string \"_ZZZAA_\" two times."}],"translated_statement":null,"sample_group":[],"show_order":[],"formal_statement":null,"simple_statement":null,"has_page_source":false}