#include <bits/stdc++.h>
using namespace std;
int a, b, c, i, k;
string str;
int main() {
  while (cin >> str) {
    k = 0;
    for (i = 0; i < str.size(); i++) {
      if (str[i] != 'a' && k == 0) k = 1;
      if (str[i] == 'a' && k == 1) {
        k = 2;
        break;
      }
      if (k == 1) str[i] = str[i] - 1;
    }
    if (k == 0) str[str.size() - 1] = 'z';
    cout << str << endl;
  }
  return 0;
}
