#include <stdio.h>

int main(void)
{
	char str[10001];
	int i = 0, j = 0;
	scanf("%s", str);

	while (str[i] != '\0') {
		if ((int)str[i] >= 49 && 57 >= (int)str[i]) {
			j += (int)str[i]-48;
		}
		i++;
	}
	printf("%d\n", j);

	return 0;
}