#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
vector<long long int> v;
vector<long long int> w, ab, bc;
set<long long int> uo;
map<long long int, long long int> ww, cc, u;
vector<pair<long long int, long long int> > uu, su;
map<long long int, vector<long long int> > uuu;
map<pair<long long int, long long int>, long long int> vo;
map<pair<long long int, long long int>, long long int> vu;
map<long long int, pair<long long int, pair<long long int, long long int> > >
    vs;
long long int dxx[] = {-1, 0, 1, 0};
long long int dyy[] = {0, 1, 0, -1};
long long int dx[] = {2, 1, -1, -2, -2, -1, 1, 2};
long long int dy[] = {1, 2, 2, 1, -1, -2, -2, -1};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  char ch;
  string a, b, c;
  double x, y, d, e, f, g, h;
  long long int n, m, i, j, k, p, q, o, l, s, tt = 1, t, z, aa, r = 0;
  for (long long int mau = 1; mau <= tt; mau++) {
    v.clear();
    w.clear();
    ww.clear();
    uu.clear();
    uo.clear();
    vo.clear();
    vu.clear();
    ab.clear();
    bc.clear();
    cc.clear();
    uuu.clear();
    a.clear();
    b.clear();
    c.clear();
    u.clear();
    cin >> n >> m;
    for (i = 1; i <= m; i++) {
      cin >> p >> q;
      ww[p]++;
      ww[q + 1]--;
    }
    s = 0;
    for (i = 1; i <= n; i++) {
      s += ww[i];
      if (s > 0) {
        v.push_back(i);
      }
    }
    sort(v.begin(), v.end());
    u[0] = 1;
    for (i = 1; i <= (n - 1); i++) {
      for (j = 0; j < v.size(); j++) {
        if (i >= v[j]) {
          u[i] += (u[i - v[j]]);
          u[i] %= 998244353;
        } else {
          break;
        }
      }
    }
    cout << u[n - 1] % 998244353 << "\n";
  }
  return 0;
}
