#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	ll N, S;
	cin >> N >> S;
	
	vector<ll> fact(S + 1);
	fact[0] = 1;
	FOR(i, 1, fact.size()) fact[i] = fact[i - 1] * i;
	
	vector<int> perm(S);
	vector<bool> done(S);
	ll cur = N;
	REP(i, perm.size()) {
		int rank = i + 1 < perm.size() ? cur / fact[S - i - 1] : cur;
		REP(j, done.size()) {
			if (done[j]) continue;
			if (rank == 0) {
				perm[i] = j;
				done[j] = true;
				break;
			}
			--rank;
		}
		cur = cur % fact[S - i - 1];
	}
	
	vector<int> rev(S);
	done.assign(S, false);
	REP(i, perm.size()) rev[perm[i]] = i;
	ll ans = 0;
	REP(i, rev.size()) {
		int rank = 0;
		REP(j, rev[i]) if (!done[j]) ++rank;
		done[rev[i]] = true;
		ans += rank * fact[S - i - 1];
	}
	cout << ans << endl;
}