A1038

#include<iostream>
#include<vector>
#include<algorithm>
#include<map>

using namespace std;
bool cmp(string a,string b){
	return a+b<b+a;
}
int main(){
	vector<string>v;
	vector<string>vv;
	map<string,string>mp;
	int n;
	string s,res;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>s;
		v.push_back(s);
	}
	
	
	sort(v.begin(),v.end(),cmp);
	for(int i=0;i<v.size();i++){
		res+=v[i];
	}
	while(res.length() != 0 && res[0] == ‘0‘)
        res.erase(res.begin());
    if(res.length() == 0) cout << 0;
    else
    cout << res;
	return 0;
}