#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	int ans = 0;
	string S;
	cin >> S;
	for (int i = 0; i < S.size(); i++) {
		if ('0' <= S[i] && S[i] <= '9') {
			ans += (int)(S[i] - '0');
		}
	}

	cout << ans << endl;

	return 0;
}