432A - Choosing Teams - CodeForces Solution

if __name__ == '__main__':
    x = input().split()
    n = int(x[0])
    k = int(x[1])
    x = input().split()
    li = [int(i) for i in x]
    for i in li:
        if i > 5 - k:
            n -= 1
    print(n//3)