#include <bits/stdc++.h>
#pragma comment(linker, "/stack:512000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
#pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
mt19937_64 gen(time(nullptr));
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
ll mod = 1e9 + 7;
namespace {
ll mul(ll a, ll b) {
  ll val = a * b - (ll)((ld)a * b / mod) * mod;
  if (val < 0) val += mod;
  if (val >= mod) val -= mod;
  return val;
}
ll poww(ll a, ll b) {
  ll val = 1;
  a %= mod;
  while (b > 0) {
    if (b % 2) val = mul(a, val);
    a = mul(a, a);
    b >>= 1;
  }
  return val % mod;
}
ll inv(ll a) { return poww(a, mod - 2); }
ll gcd(ll a, ll b) { return (a == 0 ? b : gcd(b % a, a)); }
ll gcdex(ll a, ll b, ll& x, ll& y) {
  if (a == 0) {
    x = 0;
    y = 1;
    return b;
  }
  ll x1, y1;
  ll d = gcdex(b % a, a, x1, y1);
  x = y1 - (b / a) * x1;
  y = x1;
  return d;
}
ll inv_eu(ll a, ll m) {
  ll x, y;
  ll g = gcdex(a, m, x, y);
  if (g != 1)
    assert(0);
  else {
    x = (x % m + m) % m;
    return x;
  }
}
}  // namespace
ll const maxn = 1e6 + 6;
ll fw[maxn];
void upd(ll r, ll add) {
  for (++r; r < maxn; r += -r & r) {
    (fw[r] += add) %= mod;
    if (fw[r] < 0) fw[r] += 0;
  }
}
void upd(ll l, ll r, ll add) {
  upd(r + 1, -add);
  upd(l, add);
}
ll get(ll pos) {
  ll ret = 0;
  for (++pos; pos > 0; pos -= -pos & pos) {
    (ret += fw[pos]) %= mod;
  }
  return ret;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  mod = 998244353;
  ll n, k;
  cin >> n >> k;
  vector<pair<ll, ll>> s(k);
  for (ll i = 0; i < k; i++) {
    cin >> s[i].first >> s[i].second;
  }
  upd(1, 1, 1);
  for (ll i = 1; i <= n; i++) {
    for (auto& p : s) {
      ll l = p.first, r = p.second;
      upd(i + l, i + r, get(i));
    }
  }
  cout << get(n) << endl;
  return 0;
}
