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