codeforces 632C C. The Smallest String Concatenation(sort)

You'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.

Input

The 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.

Output

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

Examples

input

4
abba
abacaba
bcd
er

output

abacabaabbabcder

input

5
x
xx
xxa
xxaa
xxaaa

output

xxaaaxxaaxxaxxx

input

3
c
cb
cba

output

cbacbc
题意：给你n个字符串,输出字典序最小的排序;
思路：写个比较函数cmp(),sort一下再输出就好了;
AC代码：

#include <bits/stdc++.h>
using namespace std;
const int N=1e4+4;
string str[6*N];
int n;
int cmp(string x,string y)
{
   return x+y<y+x;
}
int main()
{
    scanf("%d",&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;
}