#include <iostream>
using namespace std;

int main() {
	int x1,y1,x2,y2,x3,y3;
	cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
	if ((x1==x2 && y1==y2) || (x2==x3 && y2==y3) || (x3==x1 && y3==y1)) cout << "no";
	else cout << "yes";
	return 0;
}