#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<vector<ll>> vvll;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  string s;
  cin>>s;
  rep(i,s.size()){
    char c=s[i];
    if (c-'a'<i+1) c+=26;
    c-=i+1;
    cout<<c;
  }
  cout<<endl;
  return 0;
}