#include <bits/stdc++.h>
using namespace std;
int main() {
  string str;
  long long int l, i, j, k, count = 0;
  cin >> str;
  l = str.length();
  for (i = 0; i < l; i++) {
    if (str[i] == 'a') {
      count++;
    }
    if (str[i] != 'a') {
      break;
    }
  }
  if (count == l) {
    for (k = 0; k < l - 1; k++) cout << str[k];
    cout << "z";
  } else {
    for (j = i; j < l; j++) {
      if (str[j] == 'a')
        break;
      else
        str[j] = str[j] - 1;
    }
    cout << str;
  }
  return 0;
}
