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

public class LargeFactorial {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.print("Enter an integer: ");
    int n = input.nextInt();
    System.out.println(n + "! is \n" + factorial(n));
  }

  public static BigInteger factorial(long n) {
    BigInteger result = BigInteger.ONE;
    for (int i = 1; i <= n; i++)
      result = result.multiply(new BigInteger(i+""));

    return result;
  }
}