#include <stdint.h>
#include <stdio.h>

int main(void)
{
	char c;
	int sum = 0;
	while ((c = getchar()) != '\n') {
		if (c >= '0' && c <= '9') {
			sum += c - '0';
		}
	}
	printf("%d\n", sum);
	return 0;
}