#include <bits/stdc++.h>
#define fo(name) if (fopen(name".inp", "r")){ freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define fast_io ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define ll long long
using namespace std;
bool check(string a,string b){
	return a+b>b+a;
}
void solve(){
	string n;
	vector<string> a;
	while (cin>>n) a.push_back(n);
	sort(a.begin(),a.end(),check);
	for (ll i=0;i<a.size();i++) cout<<a[i];
}
int main(){
    fast_io
    fo("numcon");
    ll t=1; // cin>>t;
    while (t--) solve();
	return 0;
}
 

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