Advent of code 2021 day 10 part 2

with open('input10.txt') as r:
    l = r.read().split("\n")
cl = {'(':')','[':']','{':'}','<':'>'}

def checkrow(i):
    chunks = []
    for j in i:
        if j in cl:
            chunks.append(j)
        else:
            if j != cl[chunks.pop()]:
                return -1
    points = 0
    for i in chunks[::-1]:
        points = points*5+' ([{<'.index(i)
    return points

scores = list(filter(lambda a: a != -1,[checkrow(i) for i in l]))
print(sorted(scores)[len(scores)//2])