Problem P37297: Control C101A

/*
* Copyright (C) 2013, xerpi
*/


#include <iostream>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int suma = 0;
    for (int i = 0; i < 3; ++i) {
        suma += n%10;
        n /= 10;
    }
    cout << suma << endl;
}