def HammingDistance(p,q):
    '''return the number of different characters between p and q'''
    if len(p) != len(q):
        print("Two strings' length are not equal!")
    else:
        distances=0
        for i in range(len(q)):
            if p[i] == q[i]:
                distances = distances
            else:
                distances += 1
    print(distances)
