Given an integer N(0 ≤ N ≤ 10000), your task is to calculate N!

Input

One N in one line, process to the end of file.

Output

For each N, output N! in one line.

Sample Input

1
2
3

Sample Output

1
2
6

代码

import java.math.*;
import java.util.*;

public class Test {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNextBigInteger()){
            int n=sc.nextInt();
            System.out.println(getSum(n));
        }

    }
    public static BigInteger getSum(int n){
        if(n==0||n==1)
        {
            return BigInteger.valueOf(1);
        }
        for(int i=2;i<=n;i++)
        {
            return BigInteger.valueOf(n).multiply(getSum(n-1));
        }
        return null;
    }
}

。multiply（乘）。
BigInteger 可以用来解决数据的溢出问题。
BigInteger方法总结
https://www.cnblogs.com/qingtianxt/p/5957013.html