#include <bits/stdc++.h>
using namespace std;
string s;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> s;
  int si = s.size();
  int p1 = 0, p2;
  while (p1 < si && s[p1] == 'a') p1++;
  p2 = p1;
  while (p2 < si && s[p2] != 'a') p2++;
  if (p1 != p2) {
    for (int i = p1; i < p2; i++) s[i]--;
    cout << s << '\n';
  } else {
    s[si - 1] = 'z';
    cout << s << "\n";
  }
}
