#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
int main(){
  int N, Q;
  cin >> N >> Q;
  vector<int> L(Q), R(Q);
  for (int i = 0; i < Q; i++){
    cin >> L[i] >> R[i];
    L[i]--;
  }
  int N2 = (N + 1) / 2 * 2;
  L.push_back(0);
  R.push_back(N2);
  Q++;
  vector<vector<int>> E(Q);
  for (int i = 0; i < Q; i++){
    for (int j = i + 1; j < Q; j++){
      if (L[i] == L[j]){
        E[i].push_back(j);
        E[j].push_back(i);
      } else if (L[i] < L[j] && L[j] <= R[i] && R[i] <= R[j]){
        E[i].push_back(j);
        E[j].push_back(i);
      } else if (L[j] < L[i] && L[i] <= R[j] && R[j] <= R[i]){
        E[i].push_back(j);
        E[j].push_back(i);
      }
    }
  }
  vector<int> L2, R2;
  int Q2 = 0;
  vector<bool> used(Q, false);
  for (int i = 0; i < Q; i++){
    if (!used[i]){
      used[i] = true;
      queue<int> q;
      q.push(i);
      vector<int> X;
      while (!q.empty()){
        int v = q.front();
        q.pop();
        X.push_back(L[v]);
        X.push_back(R[v]);
        for (int w : E[v]){
          if (!used[w]){
            used[w] = true;
            q.push(w);
          }
        }
      }
      sort(X.begin(), X.end());
      X.erase(unique(X.begin(), X.end()), X.end());
      int cnt = X.size();
      for (int j = 0; j < cnt - 1; j++){
        L2.push_back(X[j]);
        R2.push_back(X[j + 1]);
        Q2++;
      }
    }
  }
  bool ok = true;
  for (int i = 0; i < Q2; i++){
    if ((R2[i] - L2[i]) % 2 == 1){
      ok = false;
    }
  }
  if (!ok){
    cout << 0 << endl;
  } else {
    vector<long long> inv(N2 + 1);
    inv[1] = 1;
    for (int i = 2; i <= N2; i++){
      inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    }
    vector<long long> fact(N2 + 1), finv(N2 + 1);
    fact[0] = 1;
    finv[0] = 1;
    for (int i = 1; i <= N2; i++){
      fact[i] = fact[i - 1] * i % MOD;
      finv[i] = finv[i - 1] * inv[i] % MOD;
    }
    vector<long long> cat(N2 / 2 + 1);
    for (int i = 0; i <= N2 / 2; i++){
      cat[i] = fact[i * 2] * finv[i] % MOD * finv[i + 1] % MOD;
    }
    long long ans = 1;
    for (int i = 0; i < Q2; i++){
      vector<pair<int, int>> P;
      for (int j = 0; j < Q2; j++){
        if (L2[i] < L2[j] && R2[j] < R2[i]){
          P.push_back(make_pair(L2[j], R2[j]));
        }
      }
      sort(P.begin(), P.end());
      int cnt = P.size();
      int a = (R2[i] - L2[i]) / 2;
      if (cnt != 0){
        vector<pair<int, int>> P2;
        P2.push_back(P[0]);
        for (int j = 1; j < cnt; j++){
          if (P[j].first <= P2.back().second){
            P2.back().second = max(P2.back().second, P[j].second);
          } else {
            P2.push_back(P[j]);
          }
        }
        int cnt2 = P2.size();
        for (int j = 0; j < cnt2; j++){
          a -= (P2[j].second - P2[j].first) / 2;
        }
      }
      ans *= cat[a];
      ans %= MOD;
    }
    ans *= fact[N / 2];
    ans %= MOD;
    ans *= fact[(N + 1) / 2];
    ans %= MOD;
    cout << ans << endl;
  }
}