#include <string.h>
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    cin >> N;
    vector<string>S(N);
    for(int i = 0; i < N; i++) {
        cin >> S[i];
    }
    string ans = S[0];
    for(int i = 1; i < N; i++) {
        string nxt = "";
        int id = 0,id2 = 0;
        while(true) {
            if(id == ans.size()) {
                if(id2 == S[i].size()) break;
                nxt += S[i][id2];
                id2++;
                continue;
            }
            if(id2 == S[i].size()) {
                nxt += ans[id];
                id++;
                continue;
            }
            if(ans[id] < S[i][id2]) {
                nxt += ans[id];
                id++;
                continue;
            }
            nxt += S[i][id2];
            id2++;
            continue;
        }
        ans = nxt;
    }
    cout << ans << "\n";
}