n=int(input())
a=list(map(int,input().split()))
x=int(input())
js=0
for i in range(n):
    if (abs(a[i]-x)<=5):
        js=js+1
print(js)
/**************************************************************
	Problem: 1964
	User: admin
	Language: Python
	Result: Accepted
	Time:343 ms
	Memory:34480 kb
****************************************************************/