#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int MOD = 998244353;
struct mint {
  ll x;
  mint(ll x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  mint& operator+=(const mint a) {
    if ((x += a.x) >= MOD) x -= MOD;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += MOD - a.x) >= MOD) x -= MOD;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint operator+(const mint a) const { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= a; }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  mint inv() const { return pow(MOD - 2); }
  mint& operator/=(const mint a) { return *this *= a.inv(); }
  mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
struct combination {
  vector<mint> fact, ifact;
  combination(int n) : fact(n + 1), ifact(n + 1) {
    assert(n < MOD);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n] * ifact[k] * ifact[n - k];
  }
  mint p(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n] * ifact[n - k];
  }
};
mint dp[200005];
mint imos[200005];
int main() {
  int N, K;
  cin >> N >> K;
  vector<P> LR(N);
  for (int i = 0; i < (K); ++i) cin >> LR[i].first >> LR[i].second;
  dp[0] = 1;
  for (int i = 0; i < N; i++) {
    if (i > 0) {
      imos[i] += imos[i - 1];
      dp[i] += imos[i];
    }
    for (auto p : LR) {
      int left = i + p.first;
      if (left >= N) continue;
      int right = min(N - 1, i + p.second);
      imos[left] += dp[i];
      imos[right + 1] -= dp[i];
    }
  }
  cout << dp[N - 1] << '\n';
  return 0;
}
