#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
string second;
int main() {
  cin >> second;
  int i = 0, n = second.size();
  for (; i < n && second[i] == 'a'; i++)
    ;
  if (i == n)
    second[n - 1] = 'z';
  else
    for (; i < n && second[i] != 'a'; i++) second[i]--;
  cout << second;
}
