#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main(){
	string s;
	int sum = 0;
	int n;
	cin >> s;
	for (int i = 0; s[i] != '\0'; ++i)
	{
		if (s[i]>='0' && s[i]<='9')
		{
			n = s[i] - '0';
			sum += n;
		}
	}
	cout << sum << endl;

}