#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
const int mod = 998244353;
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;
  }
  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(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, mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
int main(void) {
  int n, k;
  cin >> n >> k;
  int l[k], r[k];
  for (int i = 0; i < k; i++) {
    cin >> l[i] >> r[i];
  }
  set<int> s;
  for (int i = 0; i < k; i++) {
    for (int j = l[i]; j <= r[i]; j++) s.insert(j);
  }
  mint dp[n + 1];
  for (int i = 0; i < n + 1; i++) dp[i] = 0;
  dp[1] = 1;
  for (int i = 1; i <= n; i++) {
    for (auto j = s.begin(); j != s.end(); j++) {
      if (dp[i].x != 0) dp[i + *j] += dp[i];
    }
  }
  cout << dp[n];
  return 0;
}
