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

int main()
{
	char str[1111];
	int ans = 0;

	cin >> str;

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

	cout << ans << endl;

	
	return 0;
}