#include <bits/stdc++.h>
#define db double
#define il inline
#define re register
#define ll long long
#define ui unsigned
#define ull ui ll
#define i128 __int128
#define pii pair<int, int>
#define fi first
#define se second
#define eb emplace_back
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(), v.end()
#define mems(v, x) memset(v, x, sizeof(v))
#define memc(a, b) memcpy(a, b, sizeof(a))
#define FOR(i, L, R) for(re int i = (L); i <= (R); ++i)
#define ROF(i, R, L) for(re int i = (R); i >= (L); --i)
#define LS i << 1, l, mid
#define RS i << 1 | 1, mid + 1, r
#define popc(x) __builtin_popcount(x)
using namespace std;
#define N 20005
#define M 2019
const ll INF = 1e18;
ll n, m;
il void WORK() {
  m = min(m, n - m);
  if(m > 40) {cout << INF << "\n"; return ;}
  vector<ll> s;
  FOR(i, 0, m - 1) s.eb(n - i);
  FOR(i, 1, m) {
    ll k = i;
    for(auto &x : s) {
      ll g = __gcd(x, k);
      x /= g, k /= g;
    }
  }
  ll ans = 1;
  for(auto x : s) if(ans > (INF / x)) ans = INF; else ans *= x;
  cout << ans << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  while(cin >> n >> m) WORK();
  cerr << 1.0 * clock() / CLOCKS_PER_SEC;
  return 0;
}