#include <iostream>

using namespace std;
int ls,ld,mid,a,n,v[100];
int cautareBinara (int a)
{
	ls=1;
	ld=n;
	mid=(ls+ld)/2;
	while(ls <= ld)
	{
		if(a==v[mid])
		{
			return 1;
		}
		if(a<v[mid])
		{
			ld=mid;
			mid=(ls+ld)/2;
		}
		if(a>v[mid])
		{
			ls=mid+1;
			mid=(ls+ld)/2;
		}
		
	}
return 0;	
	
}
	

int main () 
{
	int i;
	cin >> n;
	for(i=1;i<=n;i++)
		cin>>v[i];
	
	cin >> a;
		
	cout << cautareBinara(a);
	
return 0;

}