Light

#include<iostream>
#include<cmath>


using namespace std;

int light(int n){

int root  = sqrt(n);
int count = 0;
for(int i =1;i<=root;i++){
	if(n%i==0){
		int div = n/i;
		if(div ==i){
			count += 1;
		}
		else{
			count += 2;
		}
	}

}
if(count%2==0)
	return 0;
else
	return 1;

}



int main(){

long long n;

while(1){
	cin >> n;
	if(n==0)
		break;
	else{
		int checker = light(n);
		if(checker==0)
			cout << "no" << '\n';
		else
			cout << "yes" << '\n';
	}
}





	return 0;
}