358

//358
#include <iostream>
#include <cstdio>
using namespace std;

int main(void) {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);

    int n, sum = 0;
    cin >> n;
    sum += n % 10;
    n /= 10;
    sum += n % 10;
    sum += n / 10;
    cout << sum << "\n";
    return 0;
}