import java.util.Scanner;
public class java{
    public static void main(String [] args){
        Scanner sa=new Scanner(System.in);
        int n,i,f;
        f=1;
        System.out.println("Ecrire un entier: ");
        n=sa.nextInt();
        for(i=1;i<=n;i++){
            f=f*i;
            
        }
        System.out.println(f);
        System.out.println("\n");
        
    }
}