#include <iostream>

using namespace std;

char decrypt(char c, int i) {
    char a;
    int offset;

    if ('a' <= c && c <= 'z') {
        a = 'a';
    } else {
        a = 'A';
    }
    offset = c - a;
    offset -= i;
    while (true) {
        if (offset >= 0) {
            return (char)(offset + a);
        }
        offset += 26;
    }
}

int main() {
    string s;

    cin >> s;
    for (int i = 0; i < s.size(); i++) {
        s[i] = decrypt(s[i], i+1);
    }

    cout << s;

    return 0;
}