def hamming_dist(str1, str2):
    mismatch = 0
    #should prob check if len(str1) == len(str2)
    for i in range(len(str1)):
        c1 = str1[i]
        c2 = str2[i]
        if c1 != c2:
            mismatch += 1
    return mismatch

#print (hamming_dist("",""))
