def manip_matrice(A, B, i, j):
    m_A = len(A[0])
    m_B = len(B[0])
    count = True

    for c in range(len(A)):
        n_A = len(A[c])

        if m_A != n_A :
            count = False

    for d in range(len(B)):

        n_B = len(B[d])

        if m_B != n_B :
            count = False

    if count == True:
        if len(A[0]) != len(B):
            return "Ces matrices ne se multiplient pas"
        else:
            matrice = np.zeros(( len(A), len(B[0]) ))
            for a in range(len(A)):
                for b in range(len(B[0])):
                    for k in range(len(A[0])):
                        matrice[a][b] += A[a][k] * B[k][b];
        print(matrice)
        return matrice[i][j];
    else:
        return "Ces matrices ne se multiplient pas"