#include <stdio.h>

int main(void)
{
	char s[10001];
	scanf("%s", s);
	int i = 0, u = 0;
	while (s[i] != '\0') {
		if (s[i] >= 48 && s[i] <= 58) u += s[i] - 48;
		i++;
	}
	printf("%d\n", u);
	return 0;
}