#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  string s;
  cin >> s;
  int f = 0;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] != 'a') f = 1;
  }
  if (f == 0) {
    for (int i = 0; i < s.size() - 1; i++) cout << "a";
    cout << "z";
    return 0;
  }
  f = 0;
  for (int i = 0; i < s.size(); i++) {
    if (f == 0 && s[i] == 'a') {
      cout << "a";
      continue;
    }
    if (s[i] != 'a') {
      f = 1;
      cout << (char)(s[i] - 1);
    }
    if (f == 1 && s[i] == 'a') {
      for (int j = i; j < s.size(); j++) cout << s[j];
      return 0;
    }
  }
  return 0;
}
