The Smallest String Concatenation

强大的stl，还有这种操作~~

You're given a list of n strings a₁, a₂, ..., a_n. 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.

Input

The first line contains integer n — the number of strings (1 ≤ n ≤ 5·10⁴).

Each of the next n lines contains one string a_i (1 ≤ |a_i| ≤ 50) consisting of only lowercase English letters. The sum of string lengths will not exceed 5·10⁴.

Output

Print the only string a — the lexicographically smallest string concatenation.

Example

Input

4abbaabacababcder

Output

abacabaabbabcder

Input

5xxxxxaxxaaxxaaa

Output

xxaaaxxaaxxaxxx

Input

3ccbcba

Output

cbacbc

#include<iostream>#include<string>#include<algorithm>#define maxn 50005using namespace std;bool cmp(string a,string b){return a+b<b+a;}int main(){int n;string str[maxn];cin >>n;for(int i=0;i<n;i++)cin >>str[i];sort(str,str+n,cmp);for(int i=0;i<n;i++)cout <<str[i];return 0; }