hdu 1042(java大数)

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

public class NF
{
public static void main(String args[])
    {
int n;
        Scanner cin = new Scanner(System.in);
        BigInteger sum;
while (cin.hasNextInt())
        {
            n = cin.nextInt();
            sum = new BigInteger("1");
for (int i=1; i<=n; ++i)
            {
                sum = sum.multiply(BigInteger.valueOf(i));
            }
            System.out.println(sum);
        }
    }
}