#include<iostream>
#include<string>

#define DEBUG

using namespace std;

int main(){
    string S;

    cin>>S;

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