import java.util.Scanner;
import java.math.BigInteger;
public class T5
{
public static void main(String[] args)
{
int a;
int b=1;
System.out.println("请输入要求阶乘的数:");
Scanner sc=new Scanner(System.in);
a=sc.nextInt();
BigInteger d=BigInteger.valueOf(1);
do
{
d=d.multiply(BigInteger.valueOf(b));
b++;
}while(b<=a);
System.out.println("所求的数的阶乘是:"+d);
}
}