#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
const double pi = acos(-1.0), eps = 1e-9, e = exp(1.0);
const int INF = 1000 * 1000 * 1000 + 5, MAXN = 100005, MOD = 1000000007,
          MAXBIT = 30;
const long long INFL = 1e+18;
void prepare(string s) {
  if ((int)s.size() != 0) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
  }
}
string s;
void solve() {
  cin >> s;
  int ind = -1;
  for (int i = 0; i < (int)s.size(); ++i) {
    if (s[i] != 'a') {
      ind = i;
      break;
    }
  }
  if (ind == -1) {
    s[(int)s.size() - 1] = 'z';
    cout << s;
  } else {
    for (int i = ind; i < (int)s.size(); i++) {
      if (s[i] == 'a') break;
      s[i]--;
    }
    cout << s;
  }
}
int main() {
  prepare("");
  solve();
  return 0;
}
