#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

mint memo[101]{1,295201906,160030060,957629942,545208507,213689172,760025067,939830261,506268060,39806322,808258749,440133909,686156489,741797144,390377694,12629586,544711799,104121967,495867250,421290700,117153405,57084755,202713771,675932866,79781699,956276337,652678397,35212756,655645460,468129309,761699708,533047427,287671032,206068022,50865043,144980423,111276893,259415897,444094191,593907889,573994984,892454686,566073550,128761001,888483202,251718753,548033568,428105027,742756734,546182474,62402409,102052166,826426395,159186619,926316039,176055335,51568171,414163604,604947226,681666415,511621808,924112080,265769800,955559118,763148293,472709375,19536133,860830935,290471030,851685235,242726978,169855231,612759169,599797734,961628039,953297493,62806842,37844313,909741023,689361523,887890124,380694152,669317759,367270918,806951470,843736533,377403437,945260111,786127243,80918046,875880304,364983542,623250998,598764068,804930040,24257676,214821357,791011898,954947696,183092975,613786113};

pair<int, mint> fact(int n) {
  int q = n / 10000000;
  mint res = memo[q];
  for (int i = q * 10000000 + 1; i <= n; i++) {
    if (i != 998244353) res *= i;
  }
  return {n >= 998244353, res};
}

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  // mint x = 1;
  // cout << 1 << ',';
  // for (int i = 1; i <= 1000000000; i++) {
  //   if (i !=998244353) x *= i;
  //   if (i % 10000000 == 0) {
  //     assert(memo[i/10000000] == x);
  //     cout << x.val() << ',';
  //   }
  // }
  // cout << endl;
  int n, k;
  cin >> n >> k;
  auto [a, v] = fact(n);
  auto [b, w] = fact(k);
  auto [c, x] = fact(n - k);
  v /= w * x;
  a -= b + c;
  if (a) v = 0;
  cout << v.val() << '\n';
}