#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;

using ll = int64_t;
using ul = uint64_t;
using ld = long double;
using vi = vector<int>;
using vd = vector<double>;
using vc = vector<char>;
using vs = vector<string>;
using vb = vector<bool>;
using vl = vector<ll>;
using vvi = vector<vi>;
using vvd = vector<vd>;
using vvc = vector<vc>;
using vvb = vector<vb>;
using vvl = vector<vl>;
using mint = modint998244353;
using vm = vector<mint>;

int main() {
  cout << "AA" << endl;
  for (int i = 0; i < 26; i++) {
    for (int j = 1; i + j < 26; j++) {
      cout << char('A' + i) << char('A' + i + j) << endl;
      if (i == 0) cout << char('A' + j) << char('A' + j) << endl;
      if (i + j < 25) cout << char('A' + i + j) << char('A' + i) << endl;
      else if (i < 25) cout << char('A' + i + j) << char('A' + i + 1) << endl;
      else cout << "ZA" << endl;
    }
  }
  return 0;
}