#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, t = 0, k;
  cin >> n >> k;
  if (n > k) n = k;
  long long unsigned int sum = 1;
  while (n != 1) {
    sum *= n;
    n--;
  }
  cout << sum;
  return 0;
}
