#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << '\n';
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cout.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
long long pows(long long a, long long b) {
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a;
    a = a * a;
    b >>= 1;
  }
  return res;
}
long long powm(long long x, long long y, long long m = 998244353) {
  x = x % m;
  long long res = 1;
  while (y) {
    if (y & 1) res = res * x;
    res %= m;
    y = y >> 1;
    x = x * x;
    x %= m;
  }
  return res;
}
long long modInverse(long long a, long long m = 998244353) {
  return powm(a, m - 2, m);
}
long long ar[200005];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, m, i, j, k, x, y, z, t, e, f, p, q, g, l, r, o, w, h,
      count1 = 0, prod = 1, a, b, c, d, index, x1, x2, y1, y2, diff, ans = 0,
      sum = 0, sum1 = 0, sum2 = 0, flag = 0, flag1 = 0, flag2 = 0;
  string s, s1, s2;
  cin >> n >> k;
  vector<long long> v;
  map<long long, long long> m1;
  for (i = 0; i < k; i++) {
    cin >> a >> b;
    for (j = a; j <= b; j++) {
      m1[j]++;
    }
  }
  for (auto i : m1) {
    v.push_back(i.first);
  }
  ar[1] = 1;
  for (i = 1; i <= n; i++) {
    for (j = 0; j < v.size(); j++) {
      if (i + v[j] <= n) {
        ar[i + v[j]] += ar[i];
        ar[i + v[j]] %= 998244353;
      } else {
        break;
      }
    }
  }
  cout << ar[n];
}
