import java.util.*;

public class Main {
    public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      long trick = sc.nextInt();
      long treat = sc.nextInt();

      long n = trick | treat;
      long factorial = 1;
      for(long i = 1; i < n; i++) {
        factorial = factorial * (i + 1);
      }

      System.out.println(factorial);
    }
}