public class Benchmark {

    protected static int global;

    public static void main(String[] args) {
        long t1 = System.nanoTime();

        int value = 0;
        for (int i = 0; i < 10000; i++) {
            value = calculatePrimeNumbers(i);
        }

        long t2 = System.nanoTime();
        System.out.println((t2 - t1) * 1e-6);
    }

    public static int calculatePrimeNumbers(int upperLimit) {

        int i = 0;
        int primeNumberCounter = 0;

        while (++i <= upperLimit) {

            int i1 = (int) Math.ceil(Math.sqrt(i));

            boolean isPrimeNumber = false;

            while (i1 > 1) {

                if ((i != i1) && (i % i1 == 0)) {
                    isPrimeNumber = false;
                    break;
                } else if (!isPrimeNumber) {
                    isPrimeNumber = true;
                }

                --i1;
            }

            if (isPrimeNumber) {
                ++primeNumberCounter;
            }
        }
        return primeNumberCounter;
    }

}