import java.math.BigInteger;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedReader;

public class Factorial_7_BufferedReader {
   public static final int MAX = 25; 
   
   public static BigInteger factorial(int n) {
     BigInteger prod = BigInteger.ONE;
     for (int i=1; i<=n; i++)
       prod = prod.multiply(new BigInteger(i +""));
     return prod;
   }
  
  public static void main(String[] args) {
     BufferedReader in = 
        new BufferedReader(
         new InputStreamReader(System.in));
     String line = "";
     System.out.print("Enter a positive integer: ");
     try {
        line = in.readLine();
     } catch (IOException e) {
        System.out.println("Could not read the input");
     }
     int n = Integer.parseInt(line);
     System.out.println(n + "! = " + factorial(n) );
  }
}