<?php
function g($x1,$y1,$x2,$y2,$x4,$y4){
	$dx1=$x1-$x4;
	$dy1=$y1-$y4;
	$dx2=$x2-$x4;
	$dy2=$y2-$y4;
	$g=$dx1*$dy2-$dx2*$dy1;
	if(0<=$g){
		return 1;
	}else{
		return -1;
	}
}
while(fscanf(STDIN,"%f %f %f %f %f %f %f %f",$x1,$y1,$x2,$y2,$x3,$y3,$x4,$y4)):
	$t=g($x1,$y1,$x2,$y2,$x4,$y4)+g($x2,$y2,$x3,$y3,$x4,$y4)+g($x3,$y3,$x1,$y1,$x4,$y4);
	if(abs($t)==3){
		printf("YES\n");
	}else{
		printf("NO\n");
	}
endwhile;
 
// your code goes here
?>

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0.0 0.0 2.0 0.0 2.0 2.0 1.5 0.5
0.0 0.0 1.0 4.0 5.0 3.0 -1.0 3.0