#include <bits/stdc++.h>
using namespace std;
int main() {
  string init;
  bool running = false;
  bool changes = false;
  cin >> init;
  for (long i = 0; i < init.size(); i++) {
    if (running) {
      if (init[i] == 'a')
        break;
      else {
        init[i]--;
        changes = true;
      }
    } else {
      if (init[i] == 'a') continue;
      running = true;
      i--;
    }
  }
  if (!changes) init[init.size() - 1] = 'z';
  cout << init << endl;
  return 0;
}
