#include <bits/stdc++.h>
using namespace std;
unsigned long long int mod = 1000000007;
using namespace std;
int main() {
  long long int q, t, i, b, d, j, k, l;
  long long int r, c, m, n, x;
  string s;
  cin >> s;
  n = s.length();
  long long int temp = 0;
  for (i = 0; i < n; i++) {
    if (s[i] != 'a') {
      s[i] = s[i] - 1;
      temp = 1;
    } else if (temp == 1)
      break;
  }
  if (temp == 0) s[n - 1] = 'z';
  cout << s << endl;
  return 0;
}
