public class PrimeNumbers {
    public static int isPrime(int n) {
        if (n <= 1) {
            return 0;
        }
        if (n <= 3) {
            return 1;
        }
        int i = 2;
        while (i * i <= n) {
            if (n - (n / i) * i == 0) {
                return 0;
            }
            i = i + 1;
        }
        return 1;
    }

    public static int main() {
        int count = 0;
        int num = 2;
        while (count < 20) {
            if (isPrime(num) == 1) {
                System.out.println(num);
                count = count + 1;
            }
            num = num + 1;
        }
        return 0;
    }
}