#include <bits/stdc++.h>
using namespace std;
using vi = vector<unsigned long long>;
using vs = vector<string>;
using vvi = vector<vi>;
using pii = pair<unsigned long long, unsigned long long>;
using vpii = vector<pii>;
using mii = map<unsigned long long, unsigned long long>;
using umii = unordered_map<unsigned long long, unsigned long long>;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (unsigned long long i = 0; i < static_cast<unsigned long long>(v.size());
       i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
unsigned long long md = 998244353;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  unsigned long long n, k;
  cin >> n >> k;
  vi a;
  for (unsigned long long i = (0); (1) > 0 ? i < (k) : i > (k); i += (1)) {
    unsigned long long x, y;
    cin >> x >> y;
    for (unsigned long long i = (x); (1) > 0 ? i < (y + 1) : i > (y + 1);
         i += (1))
      a.push_back(i);
  }
  unsigned long long x = (unsigned long long)a.size();
  sort((a).begin(), (a).end());
  vi dp(n + 1, 0);
  dp[0] = 1;
  dp[1] = 1;
  for (unsigned long long i = (1); (1) > 0 ? i < (n + 1) : i > (n + 1);
       i += (1)) {
    for (unsigned long long j = (1); (1) > 0 ? j < (x + 1) : j > (x + 1);
         j += (1)) {
      if (i > a[j - 1]) {
        dp[i] = ((dp[i] % md) + (dp[i - a[j - 1]] % md)) % md;
      } else {
        break;
      }
    }
  };
  ;
  cout << dp[n] % md;
  return 0;
}
