#include <bits/stdc++.h>
using namespace std;
const int N = 300;
int b[N];
vector<int> top16;
int toDec(string s) {
  int sum = 0;
  if (s[0] >= 'A' && s[0] <= 'F')
    sum = (s[0] - 'A' + 10) * 16;
  else
    sum = (s[0] - '0') * 16;
  if (s[1] >= 'A' && s[1] <= 'F')
    sum += (s[1] - 'A' + 10);
  else
    sum += (s[1] - '0');
  return sum;
}
string toHex(int x){
    string res;
    while(x){
        int t = x % 16;
        if(t>=10)
        res+=t-10+'A';
        else res+=t+'0';
        x/=16;
    }
    reverse(res.begin(),res.end());
    return res;
}
char find(int q){
    int mi = INT_MAX, mp = 0;
    for (int i = 0; i < top16.size();i++){
        if(abs(q-top16[i])<mi){
            mi = abs(q-top16[i]);
            mp = i;
        }
    }
    if(mp>=10)
        return (char)(mp - 10 + 'A');
        return (char)(mp + '0');
}
string c[N];
int main()
{
    int n;
    cin>>n;
    for (int i = 1;i<=n;i++){
        string s;
        cin >> s;
        c[i] = s;
        for (int j = 0; j < s.size();j+=2){
            string x;
            x.push_back(s[j]);
            x.push_back(s[j + 1]);
            b[toDec(x)]++;
        }
    }
    for (int i = 1; i <= 16;i++){
        int mx = 0, mp = 0;
        for (int j = 0; j < 256;j++)
        if(b[j]>mx){
            mx = b[j];
            mp = j;
        }
        b[mp] = 0;
        top16.push_back(mp);
    }
    for (int i = 0; i < top16.size();i++)
        cout << toHex(top16[i]);
    cout << endl;
    for (int i = 1; i <= n;i++){
        string s = c[i];
        for (int j = 0; j < s.size();j+=2){
            string x;
            x.push_back(s[j]);
            x.push_back(s[j + 1]);
            int q=toDec(x);
            cout<<find(q);
        }
        cout<<endl;
    }
        return 0; 
}