#include<iostream>
#include<string>

using namespace std;

int main(){

	string S;

	cin>>S;

	for(int i=0;i<S.size();i++){
		int c=S[i]-'A'-i-1;
		while(c<=-1) c=26+c;
		cout<<(char)(c+'A');
	}
	cout<<endl;
}