1
n, k = map(int, input().split())
2
a = sorted([int(x) for x in input().split()])
3
 
4
cur = 0
5
cnt = 0
6
 
7
for x in a:
8
    if x + k <= 5:
9
        cur += 1
10
        
11
    if cur == 3:
12
        cnt += 1
13
        cur = 0
14
 
15
print(cnt)
16
 
17