#Given 2 strings, a and b, return the number of the positions where they contain the same length 2 substring. So "xxcaazz" and "xxbaaz" yields 3, since the "xx", "aa", and "az" substrings appear in the same place in both strings.

#string_match('xxcaazz', 'xxbaaz') → 3
#string_match('abc', 'abc') → 2
#string_match('abc', 'axc') → 0

def string_match(a,b):
    if a > b :
        higher = a
    else:
        higher = b
    count = 0
    for i in range(len(higher)):
        if a[i:i+2] == b[i:i+2] and len(a[i:i+2])  == len(b[i:i+2]) == 2:
            count +=1
    return count
