#include <stdio.h>

int main(void)
{
	char st_num[10000];
	int sum = 0;
	int i = 0;
	
	scanf("%s", st_num);

	while ( st_num[i] != '\0' ) {
		if ( '0' <= st_num[i] && st_num[i] <= '9' ) {
			sum += (st_num[i] - '0');
		}
		i++;
	}
	printf("%d\n", sum);
	return 0;
}