ALGO-51 Torry的困惑(基本型)

import java.util.Scanner;

public class Main {
    static int mod = 50000;
    static final int N = 1500000;
    static boolean isPrime[] = new boolean[N + 10];
    static int prim[] = new int[150000];

    static int prime() {
        int num = 0;
        for(int i=0; i<isPrime.length; i++) {
            isPrime[i] = true;
        }
        isPrime[0] = isPrime[1] = false;
        for (int i = 2; i <= N; i++) {
            if (isPrime[i])
                prim[num++] = i;
            for (int j = 0; j < num; j++) {
                if (i * prim[j] > N)
                    break;
                isPrime[i * prim[j]] = false;
                if (i % prim[j] == 0)
                    break;
            }
        }
        return num;
    }
    
    static void pre() {
        prime();
        for(int i=1; i<100000; i++) {
            prim[i]=(prim[i-1]%mod*prim[i]%mod)%mod;
        }
    }
    public static void main(String[] args) {
        pre();
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()) {
            int n = sc.nextInt();
            System.out.println(prim[n-1]);
        }
        sc.close();
    }
}