def max_ham_overlap(a,b,max_dist):
    """ returns the length of the
   def hamming_dist(w1,w2):
    l1 = len(w1)
    l2 = len(w2)
    score = abs(len(w1) - len(w2))
    for c1,c2 in zip(w1,w2):
        if c1 != c2:
            score += 1
    return score

def max_ham_overlap(a,b,max_dist):
    distances = []
    c = min(len(a),(len(b))
    for i in range(1,c+1):
        if hamming_dist(a[-i:],b[0:i]) <= max_dist:
            distances.append(i)
    return max(distances)

print max_ham_overlap("pollock","pollers",2)