#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll MOD = 998244353;
int l[10], r[10];
ll dp[201] = {};
int main() {
  ll n, k;
  cin >> n >> k;
  for (int i = 0; i < k; ++i) cin >> l[i] >> r[i];
  dp[1] = 1;
  for (int i = 2; i <= n; ++i) {
    dp[i] = dp[i - 1];
    for (int j = 0; j < k; ++j) {
      int ll = max(1, i - r[j]);
      int rr = min(i - 1, i - l[j]);
      if (ll <= rr) {
        dp[i] += dp[rr] - dp[ll - 1];
      }
    }
    dp[i] = (dp[i] % MOD + MOD) % MOD;
  }
  cout << (dp[n] - dp[n - 1] + MOD) % MOD << endl;
  return 0;
}
