def calc_surface(l)
    return ((l[0] - l[4]) * (l[3] - l[5]) - (l[2] - l[4]) * (l[1] - l[5])).abs
end

while l=gets
    x1, y1, x2, y2, x3, y3, px, py = l.split.map(&:to_f)
    
    abc = calc_surface([x1, y1, x2, y2, x3, y3])
    pab = calc_surface([x1, y1, x2, y2, px, py])
    pbc = calc_surface([x2, y2, x3, y3, px, py])
    pca = calc_surface([x3, y3, x1, y1, px, py])
    
    if abc >= pab + pbc + pca
        puts "Yes"
    else
        puts "No"
    end
end
