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

using namespace std;

int main()
{
    vector<string> s;
    int n;
    cin>>n;
    s.resize(n);
    for(auto i:s)cin>>i;
    map<char,int> mm;
    for(int i=0;i<s[0].size();i++){
        for(auto j:s)mm[j[i]]++;
        cout<<max_element(mm.begin(),mm.end(),[](pair<char,int> a,pair<char,int> b){return a.second<b.second;})->first;
        mm.clear();
        };
    return 0;
}