#include <stdio.h>

int main() {
	static char s[10001];
	int i;
	int sum = 0;

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