#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)n; i++)
using ll = long long;

int main(){
  string s;
  cin >> s;
  rep(i,26) {
    if(s[i] != 'a' + i) {
      cout << (char)('a'+i) << "to" << s[i] << endl;
      return 0;
    }
  }
  return 0;
}