#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pl = pair<ll, ll>;
ll LINF = 1000000000000000000;
template <class T>
bool chmax(T& a, const T& b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T& a, const T& b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct UnionFind {
  vector<int> d;
  UnionFind(int n = 0) : d(n, -1) {}
  int root(int x) {
    if (d[x] < 0) return x;
    return d[x] = root(d[x]);
  }
  bool unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y) return false;
    if (d[x] > d[y]) swap(x, y);
    d[x] += d[y];
    d[y] = x;
    return true;
  }
  bool same(int x, int y) { return root(x) == root(y); }
  int size(int x) { return -d[root(x)]; }
  int factor_size() {
    int ans = 0;
    for (ll i = 0; i < (d.size()); ++i) {
      if (d[i] < 0) {
        ans++;
      }
    }
    return ans;
  }
};
ll d[100][100];
void warshall_floyd(ll n) {
  for (ll k = 0; k < (n); ++k) {
    for (ll i = 0; i < (n); ++i) {
      for (ll j = 0; j < (n); ++j) {
        d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
      }
    }
  }
}
struct edge {
  ll to, cost;
};
struct dijkstra {
  ll V;
  vector<vector<edge>> G;
  vector<ll> d;
  dijkstra(ll n) { init(n); }
  void init(ll n) {
    V = n;
    G.resize(V);
    d.resize(V);
    for (ll i = 0; i < (V); ++i) {
      d[i] = LINF;
    }
  }
  void add_edge(ll s, ll t, ll cost) {
    edge e;
    e.to = t, e.cost = cost;
    G[s].push_back(e);
  }
  void run(ll s) {
    for (ll i = 0; i < (V); ++i) {
      d[i] = LINF;
    }
    d[s] = 0;
    priority_queue<pl, vector<pl>, greater<pl>> que;
    que.push(pl(0, s));
    while (!que.empty()) {
      pl p = que.top();
      que.pop();
      ll v = p.second;
      if (d[v] < p.first) continue;
      for (auto e : G[v]) {
        if (d[e.to] > d[v] + e.cost) {
          d[e.to] = d[v] + e.cost;
          que.push(pl(d[e.to], e.to));
        }
      }
    }
  }
};
const ll mod = 1000000007;
struct mint {
  ll x;
  mint(ll x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod - a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= a; }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  mint inv() const { return pow(mod - 2); }
  mint& operator/=(const mint a) { return *this *= a.inv(); }
  mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
struct combination {
  vector<mint> fact, ifact;
  combination(int n) : fact(n + 1), ifact(n + 1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n] * ifact[k] * ifact[n - k];
  }
} comb(200005);
struct Sieve {
  int n;
  vector<int> f, primes;
  Sieve(int n = 1) : n(n), f(n + 1) {
    f[0] = f[1] = -1;
    for (ll i = 2; i <= n; ++i) {
      if (f[i]) continue;
      primes.push_back(i);
      f[i] = i;
      for (ll j = i * i; j <= n; j += i) {
        if (!f[j]) f[j] = i;
      }
    }
  }
  bool isPrime(int x) { return f[x] == x; }
  vector<int> factorList(int x) {
    vector<int> res;
    while (x != 1) {
      res.push_back(f[x]);
      x /= f[x];
    }
    return res;
  }
  vector<pl> factor(int x) {
    vector<int> fl = factorList(x);
    if (fl.size() == 0) return {};
    vector<pl> res(1, pl(fl[0], 0));
    for (int p : fl) {
      if (res.back().first == p) {
        res.back().second++;
      } else {
        res.emplace_back(p, 1);
      }
    }
    return res;
  }
  vector<pair<ll, int>> factor(ll x) {
    vector<pair<ll, int>> res;
    for (int p : primes) {
      int y = 0;
      while (x % p == 0) x /= p, ++y;
      if (y != 0) res.emplace_back(p, y);
    }
    if (x != 1) res.emplace_back(x, 1);
    return res;
  }
};
ll modmod = 998244353;
vector<ll> l(10);
vector<ll> r(10);
ll n, k;
int main() {
  cin >> n >> k;
  vector<ll> dp(200010, 0);
  vector<ll> S(200010, 0);
  for (ll i = 0; i < (k); ++i) {
    cin >> l[i] >> r[i];
    for (ll j = 0; j < (r[i] - l[i] + 1); ++j) dp[j + l[i] + 1] = 1;
  }
  for (ll i = 1; i <= (n); ++i) S[i] = S[i - 1] + dp[i];
  ll ans = 0;
  for (ll i = 1; i <= (n); ++i) {
    for (ll j = 0; j < (k); ++j) {
      if (i - l[j] > 0) {
        dp[i] += S[i - l[j]] - S[max(0LL, i - r[j] - 1)] % modmod;
      }
    }
    S[i] = S[i - 1] + dp[i];
    S[i] %= modmod;
  }
  while (dp[n] < 0) dp[n] += modmod;
  cout << dp[n] << endl;
  return 0;
}
