C. The Smallest String Concatenation

C. The Smallest String Concatenation

time limit per test

3 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

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.

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

字符串排序

#include <bits/stdc++.h>
using namespace std;

typedef long long int llint;
const int maxn = 5e4+100;
string a[maxn];

int cmp(const string &a, const string &b) {
	return a + b < b + a;
}

int main() {
	int n;
	scanf("%d",&n);
	for (int i = 0; i<n; i++)	cin >> a[i];
	sort(a, a+n, cmp);
	for (int i = 0; i<n; i++)	cout << a[i];
	cout << endl;
	return 0;
}