nyoj-28-大数阶乘

张云聪

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input=new Scanner(System.in);
		while(input.hasNext()){
			int n=input.nextInt();
			BigInteger res=F(BigInteger.valueOf(n));	
			System.out.println(res);
		}
		
	}

	private static BigInteger F(BigInteger n) {
		// TODO Auto-generated method stub
		if(n.equals( BigInteger.valueOf(1) ))
			return BigInteger.valueOf(1);
		return n.multiply(F(n.subtract( BigInteger.valueOf(1) )));
	}

}