#include <iostream>
#include <set>

using namespace std;

int main() {
    
    int n;
    cin >> n;
    
    set<int> s;
    for(int i = 0; i < n; i++) {
        int x;
        cin >> x;
        
        s.insert(x);
    }
    
    int broj;
    cin >> broj;
    
    set<int>::iterator it = s.find(broj);
    
    if(it != s.end()) {
        cout << "Postoi\n";
    }
    else {
        cout << "Ne postoi\n";
    }
    return 0;
}