#include <bits/stdc++.h>
using namespace std;

int a[110],n,x,c; 

int main(){
	cin>>n;
	int i;
	//读入数据 
	for(i = 0;i < n;i++){
		cin>>a[i];
	}
	cin>>x;
	
	//求标准零件的个数
	for(i = 0;i < n;i++){
		if(a[i] >= x - 5 && a[i] <= x + 5){
			c++;
		}
	} 
	
	cout<<c;
	
	return 0;
}

/**************************************************************
	Problem: 1964
	User: admin
	Language: C++
	Result: Accepted
	Time:42 ms
	Memory:2072 kb
****************************************************************/