#include <bits/stdc++.h>
#ifdef _DEBUG
#include "debug.hpp"
#else
#define debug(...)
#endif
#define fastIO (cin.tie(0), cout.tie(0), ios::sync_with_stdio(false))
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define precise(i) fixed << setprecision(i)
using ll = int64_t;
using ul = uint64_t;
using namespace std;

void solve() {
  string src = "abcdefghijklmnopqrstuvwxyz";
  string s;
  cin >> s;

  for(size_t i=0; i<src.size(); ++i) {
    if(s.at(i) != src.at(i)) {
      cout << src.at(i) << "to" << s.at(i) << endl;
      return;
    }
  }
}

void wrapper(){
  rep(i, 3) {
    cout << "[TEST " << i <<  "]\n";
    solve();
    cout << "\n";
  }
}

int main() {
  fastIO;
#ifdef _DEBUG
  wrapper();
#else
  solve();
#endif
}