public class PerfectNumber {
    public static void main(String[] args) {
        int n = 28, sum = 0;

        for (int i = 1; i < n; i++) {
            if (n % i == 0)
                sum += i;
        }

        if (sum == n)
            System.out.println("Perfect Number");
        else
            System.out.println("Not a Perfect Number");
    }
}