#include<cstdio>
#include<string>
bool prime[33000];
void make()
{
	int i,temp,j;
	memset(prime,true,sizeof(prime));
	prime[1]=false;
	prime[0]=false;
	for(i=2;i<=182;i++){
		j=i;
		temp=i*j;
		while(temp<=32768){
			prime[temp]=false;
			temp=i*(++j);
		}
	}
}
int main()
{
	int a,counter,i;
	make();
	while(scanf("%d",&a)&&a){
		for(counter=0,i=2;i<=a/2;i++){
			if(prime[i]&&prime[a-i]) counter++;
		}
		printf("%d\n",counter);
	}
	return 0;
}