超级大水体,主要是sort的应用。。。
#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <map>
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define ROF(i,a,b) for(int i=a;i>=b;i--)
#define mem(i,a) memset(i,a,sizeof(i))
#define rson mid+1,r,rt<<1|1
#define lson l,mid,rt<<1
#define ll long long
#define LL long long
using namespace std;
template <typename T>inline void read(T &_x_){
_x_=0;bool f=false;char ch=getchar();
while (ch<'0'||ch>'9') {if (ch=='-') f=!f;ch=getchar();}
while ('0'<=ch&&ch<='9') {_x_=_x_*10+ch-'0';ch=getchar();}
if(f) _x_=-_x_;
}
const double eps = 0.0000001;
const int maxn = 5e4+7;
const int mod = 1e9+7;
int n;
string s[maxn];
bool cmp(string c,string d){
return c+d<d+c;
}
int main(){
read(n);
FOR(i,1,n) cin>>s[i];
sort(s+1,s+1+n,cmp);
FOR(i,1,n)cout<<s[i];
printf("\n");
return 0;
}