#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

int main(){
    ll N, S;
    cin >> N >> S;
    
    vector<ll> fac(S+1, 1);
    rep(i, S+1) fac[i+1] = fac[i]*(i+1);

    vector<bool> used(S, false);
    vector<ll> P(S);
    rep(i, S){
        ll k = N/fac[S-1-i];
        int ptr = -1;
        rep(i, k+1){
            ptr++;
            while(ptr < S && used[ptr]) ptr++;
        }
        used[P[i] = ptr] = true;
        N %= fac[S-1-i];
    }
    
    vector<ll> iP(S);
    rep(i, S) iP[P[i]] = i;

    ll ans = 0;
    fill(all(used), false);
    rep(i, S){
        ll k = 0;
        rep(j, iP[i]) if(!used[j]) k++;
        used[iP[i]] = true;
        ans += fac[S-1-i]*k;
    }

    cout << ans << '\n';
}