int N;
cin >> N;
bool Flag = true;
for ( int i = 2; i < N; i++){
    if (i * i > N)
        break;
    if (N % i == 0){
        Flag = false;
        break;
    }
}
if (Flag)
    cout << N << "是质数" << endl;
else
    cout << N << "不是质数" << endl;