#include <iostream>
using namespace std;
int main() {
	char s[10000];
	int sum = 0;
	cin >> s;
	for (int i = 0; s[i]!='\0'; i++) {
		if (s[i] >= '0'&&s[i] <= '9') sum = sum + (s[i] - 48);
	}
	cout << sum << endl;
}