// PR Bab 05, tantangan -- pembahasan.

#include <iostream>
using namespace std;

int main() {
    long long n;
    cin >> n;

    if (n < 2) {
        cout << "BUKAN\n";
        return 0;
    }

    bool prima = true;
    for (long long i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            prima = false;
            break;
        }
    }

    cout << (prima ? "PRIMA" : "BUKAN") << "\n";
    return 0;
}