#include <bits/stdc++.h>
using ll = long long;
using namespace std;
void debugi(vector<int>& vec) {
  int n = (int)vec.size();
  for (int i = 0; i < n; i++) {
    cout << vec[i] << " ";
  }
  cout << endl;
}
void debugl(vector<ll>& vec) {
  int n = (int)vec.size();
  for (int i = 0; i < n; i++) {
    cout << vec[i] << " ";
  }
  cout << endl;
}
void debugmap(map<int, int>& mp) {
  for (auto x : mp) {
    cout << x.first << " " << x.second << " , ";
  }
  cout << endl;
}
void debugset(set<int>& st) {
  for (auto x : st) {
    cout << x << " ";
  }
  cout << endl;
}
void debugparri(vector<pair<int, int>>& arr) {
  for (int i = 0; i < (int)arr.size(); i++) {
    cout << "[" << arr[i].first << " : " << arr[i].second << "]"
         << " ";
  }
  cout << endl;
}
void debugpi(pair<int, int>& pi) {
  cout << pi.first << " " << pi.second << endl;
}
void debugq(queue<int> q) {
  while (!q.empty()) {
    cout << q.front() << " ";
    q.pop();
  }
  cout << endl;
}
bool check(int n, int i, int j) {
  if ((0 <= i & i < n) && (0 <= j & j < n)) {
    return true;
  }
  return false;
}
ll mod = 998244353;
ll powab(ll a, ll b, ll mod) {
  if (b == 0) {
    return 1;
  }
  ll z = powab(a, b / 2, mod);
  ll res = (z * z * 1LL) % mod;
  if (b & 1) {
    res = (res * 1LL * a) % mod;
  }
  return res;
}
int lim = 10;
int n;
vector<vector<pair<int, ll>>> g(lim);
vector<int> vis(lim);
vector<ll> dp(lim), a(lim);
int dia = 0, node = 0;
int ind = 0;
ll gcd(ll a, ll b) {
  if (b == 0) {
    return a;
  }
  return gcd(b, a % b);
}
void upd(int k, int x, vector<int>& tree, int n) {
  if (k == 0) {
    return;
  }
  while (k <= n) {
    tree[k] += x;
    k += (k & -k);
  }
}
int sum(int k, vector<int>& tree, int n) {
  int s = 0;
  while (k >= 1) {
    s += tree[k];
    k -= (k & -k);
  }
  return s;
}
int x, k;
vector<int> sieve(1000010, 0);
void fill() {
  for (int i = 2; i <= 1000004; i++) {
    if (sieve[i] == 0) {
      sieve[i] = i;
      for (int j = i; j <= 1000004; j += i) {
        sieve[j] = i;
      }
    }
  }
}
void solve() {
  int n, k;
  cin >> n >> k;
  vector<pair<int, int>> arr(k);
  for (int i = 0; i < k; i++) {
    int x, y;
    cin >> x >> y;
    arr[i].first = x;
    arr[i].second = y;
  }
  vector<ll> dp(n + 5, 0);
  dp[0] = 1;
  dp[1] = -1;
  ll s = 0, mod = 998244353;
  for (int i = 0; i < n; i++) {
    s += dp[i];
    s = (s + mod) % mod;
    for (int j = 0; j < k; j++) {
      int l = arr[j].first, r = arr[j].second;
      int low = l + i, high = min(n, r + i);
      if (low > n) {
        continue;
      }
      dp[low] += s;
      dp[high + 1] -= s;
    }
  }
  cout << s << endl;
}
int main(int argc, const char* argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  t = 1;
  for (int tt = 0; tt < t; tt++) {
    solve();
  }
  return 0;
}
