#include <bits/stdc++.h>
#pragma GCC optimize(2)
using namespace std;
int main() {
  int n, k, count = 0, minx = 9999999;
  cin >> n >> k;
  register int ans[200005] = {0};
  ans[1] = 1;
  register int yn[200005] = {0};
  for (int i = 1; i <= k; i++) {
    int a, b;
    cin >> a >> b;
    for (int i = a; i <= b; i++) {
      count++;
      yn[count] = i;
    }
    minx = min(a, minx);
  }
  for (register int i(1); i <= n - minx; ++i) {
    if (ans[i] > 0) {
      for (int j = 1; j <= count; j++) {
        int kk = i + yn[j];
        if (kk <= n) {
          ans[kk] += ans[i];
          ans[kk] %= 998244353;
        }
      }
    }
  }
  cout << ans[n] << endl;
  return 0;
}
