#include <bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
  int i, j;
  string s;
  cin >> s;
  for (j = 0; j < s.length() && (s[j] == 'a'); j++) {
  };
  if (j == s.length()) {
    s[j - 1] = 'z';
  } else {
    for (i = j; (i < s.length()) && (s[i] != 'a'); i++) {
      s[i] = s[i] - 1;
    }
  }
  cout << s;
  return 0;
}
