public class Fact {
  public static int ff(int n) {
    int fact = 1;
    for (int i = 1; i <= n; i++) {
      fact *= i;
    }
    return fact;
  }

  public static int wf(int n) {
    int fact = 1;
    while (n > 1) {
      fact *= n--;
    }
    return fact;
  }

  public static int fact(int n) {
    if (n > 1)
      return n * fact(n - 1);
    else
      return 1;
  }

  public static void main(String args[]) {
    int n = Integer.parseInt(args[0]);
    System.out.println(fact(n));
    System.out.println(wf(n));
    System.out.println(ff(n));
  }
}