#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
#define int long long

signed main(){
  int trick,treat;
  cin>>trick>>treat;
  int num=(trick | treat);
  int ans=1;
  while(num>1){
    ans*=num;
    num--;
  }
  cout<<ans<<endl;
  return 0;
}