def cp(x1,x2)
  x1[0]*x2[1]-x1[1]*x2[0]
end

def aux(p1,p2,p3,px)
  v1=[p1[0]-px[0],p1[1]-px[1]]
  v2=[p2[0]-px[0],p2[1]-px[1]]
  v3=[p3[0]-px[0],p3[1]-px[1]]
  w1=cp(v1,v2)
  w2=cp(v2,v3)
  w3=cp(v3,v1)
  if (w1 < 0 and w2 < 0 and w3 < 0) or (w1 > 0 and w2 > 0 and w3 > 0)
    return "YES"
  else
    return "NO"
  end
end

def main
  fh=STDIN
  #fh=File.new("vol0-0012.txt,"r")
  while fh.gets
    f = $_.chomp.split.map(&:to_f)
    puts aux([f[0],f[1]], [f[2],f[3]], [f[4],f[5]], [f[6],f[7]])
  end
end

if $0 == __FILE__ then
  main
end
