import java.util.*;

public class My {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int a = in.nextInt();

        if ((a >= 1) && (a <= 4)){
            System.out.println("few");
        } else if ((a >= 5) && (a <= 9)){
            System.out.println("several");
        } else if ((a >= 10) && (a <= 19)){
            System.out.println("pack");
        } else if ((a >= 20) && (a <= 49)){
            System.out.println("lots");
        } else if ((a >= 50) && (a <= 99)){
            System.out.println("horde");
        } else if ((a >= 100) && (a <= 249)){
            System.out.println("throng");
        } else if ((a >= 250) && (a <= 499)){
            System.out.println("swarm");
        } else if ((a >= 500) && (a <= 999)){
            System.out.println("zounds");
        } else if (a > 1000){
            System.out.println("legion");
        }

    }

}

Try this test:

1000

I did a test 1000