題干：

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

?

解題報(bào)告：

類似于nyoj 1233這道題（這題需要處理大數(shù)）。本題直接排序就好了。這題如果不用string的話，需要用Node結(jié)構(gòu)體存char [] ，然后對(duì)Node排序（用strcmp函數(shù)），不知道時(shí)間上會(huì)不會(huì)快一點(diǎn)？反正這個(gè)題用string類是300+ms左右。

AC代碼：

#include<cstring> #include<iostream> #include<algorithm> #include<cstdio> using namespace std; string s[50000 + 5]; int dp[1005][1005]; int len1,len2; bool cmp(string a,string b) {return a+b < b+a; } int main() {int n;cin>>n;for(int i = 1; i<=n; i++) {cin>>s[i];}sort(s+1,s+n+1,cmp); // for(int i = 1; i<=n; i++) { // cout << s[i]<<endl; // }for(int i = 1; i<=n; i++) {cout << s[i];}return 0 ; }

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