def Inside_triangle(p, a, b, c):
    """ inside_triangle(p, a, b, c)
    p: point (x,y)
    a, b, c: vertices of the triangle (x,y)

    >>> inside_triangle(p, a, b, c)
    """
    detT = (a[0]-c[0])*(b[1]-c[1]) - (a[1]-c[1])*(b[0]-c[0])
    lambda1 = ((b[1]-c[1])*(p[0]-c[0]) - (b[0]-c[0])*(p[1]-c[1])) / detT
    lambda2 = (-(a[1]-c[1])*(p[0]-c[0]) + (a[0]-c[0])*(p[1]-c[1])) / detT
    lambda3 = 1 - lambda1 - lambda2
    return (0 < lambda1 < 1) and (0 < lambda2 < 1) and (0 < lambda3 < 1)