#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 100;
const long long inf = 1e9;
long long mod = 1000000007;
int main() {
  string s;
  cin >> s;
  bool flag = false;
  int p;
  for (int(i) = (0); (i) < (s.length()); ++(i))
    if (s[i] != 'a') {
      p = i;
      flag = true;
      break;
    }
  if (flag)
    for (int(i) = (p); (i) < (s.length()); ++(i)) {
      if (s[i] == 'a')
        break;
      else
        s[i] -= 1;
    }
  else {
    s[s.length() - 1] = 'z';
  }
  cout << s << endl;
  return 0;
}
