class Solution(object):

    def numEquivDominoPairs(self, dominoes):

        """

        :type dominoes: List[List[int]]

        :rtype: int

        """

        f = {}

        ret = 0

        for d in dominoes:

            if d[0] > d[1]:

                d[0], d[1] = d[1], d[0]

            x = d[0] * 10 + d[1]

            ret += f.get(x, 0)

            f[x] = f.get(x, 0) + 1

        return ret

class Solution:

    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:

        hashmap = collections.defaultdict(int)

        for i, j in dominoes:

            if i > j:

                i, j = j, i

            hashmap[(i,j)] += 1

        ans = 0

        for key in hashmap:

            ans += hashmap[key]*(hashmap[key]-1)//2

        return an