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

int main(){
string s;
cin>>s;
char AA;
for (int i = 0; i < s.length(); ++i) {
	char c=s[i]-'A'-1-(i%26);
	if(c<0){
    AA=c+'A'+26	;
	}else{
		 AA=c+'A';
	}
	cout<<AA;
}


}