def cross(vec1, vec2)
  return vec1[0] * vec2[1] - vec1[1] * vec2[0]
end

def isIn?(c1, c2, c3)
  return (c1 > 0 && c2 > 0 && c3 > 0) || (c1 < 0 && c2 < 0 && c3 < 0) ? true : false
end

while line = gets do
  x1, y1, x2, y2, x3, y3, xp, yp = line.split.map(&:to_f)
  vec1_to_p = [xp - x1, yp - y1]
  vec2_to_p = [xp - x2, yp - y2]
  vec3_to_p = [xp - x3, yp - y3]
  vec1_to_2 = [x2 - x1, y2 - y1]
  vec2_to_3 = [x3 - x2, y3 - y2]
  vec3_to_1 = [x1 - x3, y1 - y3]

  isIn?(cross(vec1_to_p, vec1_to_2), cross(vec2_to_p, vec2_to_3), cross(vec3_to_p, vec3_to_1)) ? (puts "YES") : (puts "NO")
end