def is_intersect(ax, ay, bx, by, cx, cy, dx, dy )
  tc = (ax-bx)*(cy-ay)+(ay-by)*(ax-cx)
  td = (ax-bx)*(dy-ay)+(ay-by)*(ax-dx)
  return tc * td < 0
end

STDIN.each_line do |s|
  x1, y1, x2, y2, x3, y3, xp, yp = s.chomp.split.map &:to_f
  ctx = ( x1 + x2 + x3 ) / 3.0
  cty = ( y1 + y2 + y3 ) / 3.0

  r = !is_intersect( x1, y1, x2, y2, ctx, cty, xp, yp ) \
      && !is_intersect( x2, y2, x3, y3, ctx, cty, xp, yp ) \
      && !is_intersect( x3, y3, x1, y1, ctx, cty, xp, yp )

  puts r ? "YES" : "NO"
end