#include <stdio.h>

int main(){

	char s[10000];
	scanf("%s", s);
	int sum = 0;

	int i = 0;
	while(s[i] != '\0'){
		if(s[i] >= 48 && s[i] <= 57){
			sum += s[i] - 48;
		}
		i++;
	}

	printf("%d\n", sum);

	return 0;

}