#include <bits/stdc++.h>
using namespace std;
const long long INF = 1LL << 60;
const long long MOD = 1000000000 + 7;
const int mod = 998244353;
struct mint {
  unsigned long long x;
  mint(unsigned 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;
  }
  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(unsigned 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 { return mint(*this) /= a; }
};
istream &operator>>(istream &is, const mint &a) { return is >> a.x; }
ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> s_base;
  vector<mint> dp(2 * 100100, 0);
  for (int i = 0; i < (int)(k); i++) {
    int l, r;
    cin >> l >> r;
    for (int i = l; i <= r; i++) {
      s_base.push_back(i);
    }
  }
  sort(s_base.begin(), s_base.end());
  dp[1] = 1;
  for (int i = 1; i < n; i++) {
    if (s_base.empty()) {
      break;
    }
    vector<int> s = s_base;
    auto itr = s.begin();
    for (int j = 0; j < s_base.size(); j++) {
      if (i + s_base[j] > n) {
        s_base.erase(s_base.begin() + j);
      } else {
        dp[i + s_base[j]] += dp[i];
      }
    }
  }
  cout << dp[n] << endl;
  return 0;
}
