#include <bits/stdc++.h> using namespace std; #define REP(i,n) for(int i=0; i<(int)(n); i++) int main() { ios_base::sync_with_stdio(0); cin.tie(0); long long n; int s; cin >> n >> s; vector<int> v(s); vector<bool> used(s); vector<long long> f(s); f[0] = 1; for (int i = 1; i < s; i++) f[i] = f[i-1] * i; for (int i = 0; i < s; i++) { for (int j = 0; j < s; j++) { if (used[j]) continue; if (n == 0 || n < f[s-1-i]) { v[i] = j; used[j] = true; break; } else { n -= f[s-1-i]; } } } vector<int> w(s); for (int i = 0; i < s; i++) w[v[i]] = i; long long ret = 0; vector<bool> added(s); for (int i = 0; i < s; i++) { added[w[i]] = true; for (int j = 0; j < w[i]; j++) { if (!added[j]) { ret += f[s-1-i]; } } } cout << ret << endl; return 0; }