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

static constexpr char alpha[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

int get_alpha_index( const char& c )
{
    for( int i {} ; alpha[i] != '\0' ; ++i ) {
        if( c == alpha[i] ) {
            return i;
        }
    }
    
    return -1;
}

char decode( const char& c, int cnt )
{
    const int pos = get_alpha_index( c );
    return alpha[ abs( pos - cnt + 26 ) % 26 ];
}


int main()
{
    string s {};
    cin >> s;
    
    for( size_t i {} ; i<s.length(); ++i ) {
        s[i] = decode( s[i], i + 1 );
    }
    
    cout << s << endl;
}