HackerRank Python- No Idea

There is an array of n integers. There are also 2 disjoint sets, A and B, each containing m integers. You like all the integers in set A and dislike all the integers in set B. Your initial happiness is 0.

# Enter your code here. Read input from STDIN. Print output to STDOUT

if __name__ == "__main__":
    happiness = 0
    n, m = map(int, input().strip().split(' '))
    arr = list(map(int, input().strip().split(' ')))
    
    good = set(map(int, input().strip().split(' ')))
    bad = set(map(int, input().strip().split(' ')))
    
    for el in arr:
        if el in good:
            happiness += 1
        elif el in bad:
            happiness -= 1
    
    print(happiness)