#include <stdio.h>

int main(void) {
	char input[256] = { '\0' };
	char* p;
	int i, sum = 0;

	scanf("%s", input);

	for (p = input; *p != '\0'; p++)
		if (*p >= '0' && *p <= '9')
			sum += (*p - '0');

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

	return 0;
}