#include<iostream>
using namespace std;
int main(void)
{
	char s[10010];
	int i,ans=0;

	cin >> s;
	for (i = 0; s[i] != '\0'; i++) {
		if ('0' <= s[i] && s[i] <= '9')
			ans += s[i] - 48;
	}
	cout << ans << endl;

	return 0;
}