// координатные четверти
var s, substr, maxsubstr:string;
	maxcount, count, i, flag, x1,y1, x2,y2:integer;
begin
	readln(x1,y1);
	readln(x2,y2);
	// 1 четверть
	if(x1 > 0)and(y1 > 0)and(x2 > 0)and(y2 > 0) then
	writeln("YES")
	//2 четверть
	else if (x1 < 0)and(y1 > 0)and(x2 < 0)and(y2 > 0) then
	writeln("YES")
	//3
	else if(x1 < 0)and(y1 < 0)and(x2 < 0)and(y2 < 0) then
	writeln("YES")
	//4
	else if(x1 > 0)and(y1 < 0)and(x2 > 0)and(y2 < 0) then
	writeln("YES")
	else
	write("NO");

end.