#include <iostream>
#include <stack>
#include <algorithm>
using namespace std;

int main(void) {
	int sum = 0;
	string s;
	cin >> s;
	for(int i=0;i<s.size();i++){
		if(s[i] >= '0' && s[i] <= '9'){
			sum += (int)s[i] - '0';
		}
	}
	cout << sum << endl;
	return 0;
}