#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(int i=0;i<n;i++)
#define ALL(v) v.begin(),v.end()
constexpr ll MOD=998244353;
constexpr ll INF=1e18;

int main(){
    ll n, s; cin >> n >> s;
    VI fact(s+1);
    fact[0]=1;
    for(int i=1;i<=s;i++)
        fact[i]=fact[i-1]*i;
    VI a(s);
    vector<bool> f(s,0);
    for(int i=s-1;i>=0;i--){
        int k=n/fact[i];
        REP(j,s){
            if(!f[j]){
                if(k==0){
                    f[j]=1;
                    a[s-1-i]=j;
                    break;
                }
                k--;
            }
        }
        n%=fact[i];
    }
    VI b(s);
    REP(i,s)
        b[a[i]]=i;
    ll ans=0;
    f=vector<bool>(s,0);
    REP(i,s){
        ll c=0;
        REP(j,b[i]){
            if(!f[j])
                c++;
        }
        f[b[i]]=1;
        ans+=fact[s-1-i]*c;
    }
    cout << ans << endl;
    return 0;
}