#include <stdio.h>

int main() {

	char str[10000];
	int a = 0;

	scanf("%s", &str);

	for (int i = 0; str[i] != '\0'; i++) {
		if (str[i] <= '9' && str[i] >= '0') {
			a += (str[i] - '0');
		}
	}
	printf("%d\n", a);

	return 0;
}