#include <bits/stdc++.h>
using namespace std;

signed main(){
  string S; cin >> S;
  for( int i = 0; i < S.size(); ++i )
    cout << ( char ) ( ( ( S[ i ] - 'A' - i - 1 ) % 26 + 26 ) % 26 + 'A' );
  cout << endl;
  return 0;
}