#include <iostream>
#include <string>

using namespace std;
int main()
{
	string S;
	int ans = 0;
	cin >> S;
	for(int i=0;i<S.length();++i){
		int num = (int)S[i] - 48;
		if(num > 0 && num < 10){
			ans += num;
		}
	}
	cout << ans << endl;
	return 0;
}