#include <stdio.h>



int main(void) {
	char input[10001];
	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);
}