#include <iostream>
#include <cstdio>
using namespace std;

int main() {
	string s;
	int a=0;
	cin >> s;
	for (int i=0; i<s.size();i++){
		if(s[i]>='0'&&s[i]<='9') a+=(s[i]-48);
	}
	cout << a << endl;
	return 0;
}