大数阶乘

import java.util.Scanner;
import java.math.BigInteger;
public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        BigInteger big= BigInteger.ONE;    
        for(int i=1;i<=n;i++)
            big=big.multiply(new BigInteger(i+""));
        
        System.out.println(big);
        
        sc.close();

    }

}