#include <iostream>

using namespace std;

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