#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    string s;
    cin >> s;
    int n = s.size();
    rep(i,n){
        int a = s[i] - 'A';
        rep(j,i+1){
            a += 25;
            a %= 26;
        }
        s[i] = a + 'A';
    }
    cout << s << endl;
    return 0;
}