np.random.seed(1234)
A = np.random.randint(-2,3,size=(6,4))
b = np.random.randint(-2,3,size=(6))
C = np.random.randint(-2,3,size=(3,6))
d = np.random.randint(-2,3,size=(3))
x = np.random.randint(-2,3,size=(4))