#include<iostream>
using namespace std;

int main(){
  string s;
  cin >> s;

  string std;
  int i;
  int tmp;
  for(i=0;i<s.length();i++){
    tmp = s[i] -'A' - (i+1);
    tmp %= 26;
    if(tmp < 0)tmp += 26;
    
    std += tmp + 'A';
  }

  cout << std << endl;
  
  return 0;
}