#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
unsigned long long gcd(unsigned long long a, unsigned long long b) {
  return b ? gcd(b, a % b) : a;
}
unsigned long long lcm(unsigned long long a, unsigned long long b) {
  return a / gcd(a, b) * b;
}
const long long 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; }
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> l(k), r(k);
  for (int i = 0, i_len = (k); i < i_len; i++) cin >> l[i] >> r[i];
  set<int> st;
  for (int i = 0, i_len = (k); i < i_len; i++) {
    for (int j = l[i]; j <= r[i]; ++j) st.insert(j);
  }
  vector<mint> dp(n + 2);
  dp[1] = 1;
  for (int h = 1; h < n; ++h) {
    for (auto itr = st.begin(); itr != st.end(); ++itr) {
      if (h + (*itr) > n) break;
      dp[h + (*itr)] += dp[h];
    }
  }
  cout << dp[n] << endl;
  return 0;
}
