（Educational Codeforces Round 9 ）The Smallest String Concatenation（排序）

The Smallest String Concatenation

time limit per test3 seconds
memory limit per test256 megabytes
inputstandard input
outputstandard output

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个串，然后你要组合这n个串，使得n个串的字典序最小。

#include<bits/stdc++.h>
using namespace std;
const int maxn = 50000 + 10;
string s[maxn];
bool cmp(const string &a,const string &b){
    return a + b < b + a;
}
int main()
{
    int n;
    while(scanf("%d",&n) == 1){
        for (int i = 0; i < n; ++i)
        cin >> s[i];
        sort(s,s+n,cmp);
        for (int i = 0; i < n; ++i)
        cout << s[i];
        printf("\n");
    }
    return 0;
}