#include<stdio.h>

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

	scanf("%s", str);

	for (int i = 0; str[i] != '\0'; i++) {
		if (str[i] <= 57)
			total += str[i] - 48;
	}
	printf("%d\n", total);

	return 0;
}