#include <stdio.h>
int main(void){
	char s[10005];
	int ans = 0;
	scanf("%s", s);
	for(int i = 0; s[i] != '\0'; i++){
		if(s[i] >= '0' && s[i] <= '9'){
			ans += (s[i] - '0');
		}
	}
	printf("%d\n", ans);
	return 0;
}