#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d;
	while(cin >> a >> b >> c >> d){
		if((2*b < a*a)||(2*c != a*(3*b - a*a))||(2*(b*b - d) != (a*a - b)*(a*a - b)))
			cout << "N" << endl;
		else
			cout << "Y" << endl;  
	}	
	return 0;
}