C. The Smallest String Concatenationtime limit per test3 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou're given a list of n strings a1, a2, ..., an. You'd like to concatenate them together in some order such that the resulting string would be lexicographically smallest.Given the list of strings, output the lexicographically smallest concatenation.InputThe first line contains integer n — the number of strings (1 ≤ n ≤ 5·104).Each of the next n lines contains one string ai (1 ≤ |ai| ≤ 50) consisting of only lowercase English letters. The sum of string lengths will not exceed 5·104.OutputPrint the only string a — the lexicographically smallest string concatenation.ExamplesInput4abbaabacababcderOutputabacabaabbabcderInput5xxxxxaxxaaxxaaaOutputxxaaaxxaaxxaxxxInput3ccbcbaOutputcbacbc
Input4abbaabacababcder
Outputabacabaabbabcder
['sortings', 'strings', '*1700']