#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;
const long long INF = 1LL << 60;
const int IINF = 1000000000;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct mint {
  long long x;
  mint(long long 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;
  }
  bool operator==(const mint a) { return (x == a.x); }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(long long 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 {
    mint res(*this);
    return res /= a;
  }
};
mint pow2(mint x, long long t) { return x.pow(t); }
istream& operator>>(istream& is, const 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 choose(int n, int a) {
  mint x = 1, y = 1;
  for (int i = 0; i < (a); i++) {
    x *= n - i;
    y *= i + 1;
  }
  return x / y;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int N, K;
  cin >> N >> K;
  vector<pair<long long, long long>> LR(K);
  vector<long long> S;
  for (int i = 0; i < (K); i++) {
    cin >> LR[i].first >> LR[i].second;
  }
  for (int i = 0; i < (K); i++) {
    for (int j = LR[i].first; j <= LR[i].second; j++) {
      S.push_back(j);
    }
  }
  sort(S.begin(), S.end());
  S.erase(unique(S.begin(), S.end()), S.end());
  vector<mint> dp(N + 1, 0);
  dp[0] = 1;
  for (int j = 0; j < (N); j++) {
    for (int i = 0; i < (S.size()); i++) {
      if (j + S[i] > N) continue;
      dp[j + S[i]] += dp[j];
    }
  }
  mint ans = 0;
  ans = dp[N - 1];
  cout << ans << endl;
}
