#include <stdio.h>

int main(void) {
	char s[10001];
	int i, sum = 0;
	scanf("%s", s);
	i = 0;
	while(s[i] != '\0'){
		if(s[i] >= '0' && s[i] <= '9'){
			sum += s[i] - '0';
		}
		i++;
	}

	printf("%d\n", sum);

	return 0;
}