#include <bits/stdc++.h>
using namespace std;
template <typename T>
bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
const long long mod = 998244353;
const int inf = 1 << 30;
const long long lnf = 1ll << 60;
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; }
mint dp[10];
int main() {
  int n, k;
  cin >> n >> k;
  dp[0] = 1;
  dp[1] = -1;
  vector<int> l(k);
  vector<int> r(k);
  for (int i = 0; i < (int)(k); i++) cin >> l[i] >> r[i];
  for (int i = 0; i < (int)(n); i++) {
    if (i > 0) dp[i] += dp[i - 1];
    for (int j = 0; j < (int)(k); j++) {
      mint x = dp[i];
      if (i + l[j] < n) dp[i + l[j]] += x;
      if (i + r[j] + 1 < n) dp[i + r[j] + 1] -= x;
    }
  }
  cout << dp[n - 1] << endl;
}
