#include <bits/stdc++.h>
//#include<boost/multiprecision/cpp_int.hpp>
//#include<boost/multiprecision/cpp_dec_float.hpp>
//#include <atcoder/all>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a; i >-1; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a; i > b; --i)
#define repl(i, a) for (ll i = (ll)0; i < (ll)a; ++i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
#define fi first
#define se second
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll mod_998244353 = 998244353;
constexpr ll INF = 1LL << 60;

// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

//using lll=boost::multiprecision::cpp_int;
//using Double=boost::multiprecision::number<boost::multiprecision::cpp_dec_float<128>>;//仮数部が1024桁
template <class T>
inline bool chmin(T &a, T b)
{
	if (a > b)
	{
		a = b;
		return true;
	}
	return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
	if (a < b)
	{
		a = b;
		return true;
	}
	return false;
}

ll mypow(ll x, ll n, const ll &p = -1)
{ //x^nをmodで割った余り

	if (p != -1)
	{
		x =(x%p+p)%p;
	}
	ll ret = 1;
	while (n > 0)
	{
		if (n & 1)
		{
			if (p != -1)
				ret = (ret * x) % p;
			else
				ret *= x;
		}
		if (p != -1)
			x = (x * x) % p;
		else
			x *= x;
		n >>= 1;
	}
	return ret;
}

using namespace std;
//using namespace atcoder;

template<typename T>
struct BIT{
  //0オリジンで与える
  vector<T>bit;
  int N;

	BIT(){}

  BIT(int n):N(n){
    init(n);
  }

	void init(int n){
		bit.assign(++n,0);
	}

  T sum(int i){
    T s=0;
    ++i;//0オリジンに対応させる
    while(i>0){
      s+=bit[i];
      i-=i&-i;//iから最後の1のビットを減算
    }
    return s;
  }

  void add(int i,T x){
    ++i;//0オリジンに対応させる
    while(i<(int)bit.size()){
      bit[i]+=x;
      i+=i&-i;
    }
  }

  T Lower_bound(T k){//0-indexed
		++k;
    if(k<=0)
      return 0;
    T x = 0;
    T mul = 1;
    while (mul<N){
      mul *= 2;
    }
    for (T i = mul; i > 0;i/=2){
      if(x+i<=N&&bit[x+i]<k){
        k -= bit[x + i];
        x += i;
      }
    }
    return x;
  }
};


vector<ll>fact;
ll n,s;
vector<int>perm;

void rec(int id,ll rest,BIT<int> &bit){
	if(id==s)return;
	
	ll x=rest/fact[s-1-id];
	int val=bit.Lower_bound(x);
	perm[id]=val;
	bit.add(val,-1);

	rec(id+1,rest%fact[s-1-id],bit);
}
void solve()
{	
	cin>>n>>s;

	fact.resize(s+1,1);
	rep(i,s)fact[i+1]=fact[i]*(i+1);


	perm.resize(s);
	BIT<int>tree(s+5);
	rep(i,s+1)tree.add(i,1);
	rec(0,n,tree);
	rep(i,s){
		perm[i]++;
		//cout<<perm[i];
	}
	//cout<<"\n";
	vector<int>rev_perm(s);
	rep(i,s){
		rev_perm[perm[i]-1]=i+1;
	}
	int bit=0;
	int ope=0;
	ll ans=0;
	rep(i,s){
		bit|=1<<rev_perm[i]-1;
		ope=1<<rev_perm[i];
		ope--;
		ans+=fact[s-1-i]*(rev_perm[i]-popcount(bit&ope));
	}
	cout<<ans<<"\n";
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}