#include <bits/stdc++.h>
using namespace std;
ofstream outfile;
ifstream infile;
int main() {
  infile.open("input.txt");
  outfile.open("output.txt");
  string s;
  cin >> s;
  string fin;
  int i;
  bool flag = false;
  while (i < s.length()) {
    if (s[i] == 'a') {
      fin += 'a';
      ++i;
      continue;
    }
    while (i < s.length() && s[i] != 'a') {
      flag = true;
      fin += (char)(s[i] - 1);
      ++i;
    }
    while (i < s.length()) {
      fin += s[i];
      ++i;
    }
    break;
  }
  if (!flag) {
    fin[i - 1] = 'z';
  }
  cout << fin << "\n";
}
