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

int main() {
	int count = 0;
	string S;
	cin >> S;
	for (int i = 0; i < S.size(); i++) {
		int x = S[i];
		if (48 <= x && x <= 57) {
			count += x - 48;
		}
	}
	cout << count;
}