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

int main()
{
	char str[10000];
	int ch;
	int sum = 0;

	cin >> str;
	for (int i = 0; i < strlen(str); i++){
		if ('1' <= str[i] && str[i] <= '9'){
			ch = str[i] - '0';
			sum += ch;
		}
	}

	cout << sum << endl;

	return (0);
}