#include<iostream>
#include<string>
using namespace std;
int main() {
	string s;
	int sum=0;
	int size;

	cin >> s;
	size = s.size();
	for (int i = 0; i <=size; i++) {
		//cout << s[i]<<"\n";
		char ch = s[i];
		if (isdigit(ch)) {
			//cout << ch;
			int a=ch-'0';
			sum += a;
		}
	}
	cout << sum;
	return 0;

}