#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define fi first
#define se second
#define all(a) a.begin(),a.end()
int main(){
  int treak,treat;
  cin >> treak >> treat;
  int n=(treak | treat);
  ll ans=n;
  for(int i=2; i<n; ++i) ans*=i;
  cout << ans << endl;
  return 0;
}