#include<stdio.h>
#include<string.h>
int main(void){
	int sum=0,i;
	char c[10000];
	scanf("%s",c);
	for(i=0;i<strlen(c);i++){
		if('0' <= c[i] && c[i] <= '9') sum += c[i] - '0';
	}
	printf("%d",sum);
	return 0;
}