LeetCode - Maximum Length of Pair Chain(646)

class Solution:
    def findLongestChain(self, pairs: List[List[int]]) -> int:
        
        answer = 1
        sortedPairs = sorted(pairs, key = lambda x : x[1])
        relay = sortedPairs[0][1]
        
        for i in range(1, len(sortedPairs)):
            if sortedPairs[i][0] > relay:
                answer += 1
                relay = sortedPairs[i][1]
                
        return answer