#include <bits/stdc++.h>
// #include <atcoder/all>
// using namespace atcoder;
using namespace std;
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#ifdef LOCAL
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
#define debug(...) cerr << 'L' << __LINE__ << " [" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define dump(x) cerr << 'L' << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif
template<typename T> using V = vector<T>;
template<typename T> using P = pair<T, T>;
using ll = long long;
using ld = long double;
using Vi = V<int>;  using VVi = V<Vi>;
using Vl = V<ll>;   using VVl = V<Vl>;
using Vd = V<ld>;   using VVd = V<Vd>;
using Vb = V<bool>; using VVb = V<Vb>;
using Pi = P<int>;
using Pl = P<ll>;
using Pd = P<ld>;
template<typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<typename T> inline int sz(T &x) { return x.size(); }
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p) { os << '(' << p.first << ", " << p.second << ')'; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (auto &e : v) is >> e; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<typename T> inline int count_between(vector<T> &a, T l, T r) { return lower_bound(all(a), r) - lower_bound(all(a), l); } // [l, r)
inline ll cDiv(const ll x, const ll y) { return (x+y-1) / y; } // ceil(x/y)
inline int fLog2(const ll x) { assert(x > 0); return 63-__builtin_clzll(x); } // floor(log2(x))
inline int cLog2(const ll x) { assert(x > 0); return (x == 1) ? 0 : 64-__builtin_clzll(x-1); } // ceil(log2(x))
inline int popcount(const ll x) { return __builtin_popcountll(x); }
inline void fail() { cout << -1 << '\n'; exit(0); }
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
// const int INF  = 1<<30;
// const ll INFll = 1ll<<60;
// const ld EPS   = 1e-10;
// const ld PI    = acos(-1.0);
// const int MOD  = int(1e9)+7;
const int MOD  = 998244353;



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 -= a.x) < 0) 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& operator/=(const mint r) {
    ll a = r.x, b = MOD, u = 1, v = 0;
    while (b) {
      ll t = a / b;
      a -= t * b; swap(a, b);
      u -= t * v; swap(u, v);
    }
    x = x * u % MOD;
    if (x < 0) x += MOD;
    return *this;
  }
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
// istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
using Vm = vector<mint>;
using VVm = vector<Vm>;
using VVVm = vector<VVm>;


template<typename T>
struct Polynomial : vector<T> {
  using vector<T>::vector;
  using P = Polynomial;
  int n = (*this).size();
  P operator-() const {
    P res(n);
    rep(i, n) res[i] = -(*this)[i];
    return res;
  }
  P &operator+=(const P q) {
    rep(i, n) if (i < q.size()) (*this)[i] += q[i];
    return *this;
  }
  P &operator-=(const P q) {
    rep(i, n) if (i < q.size()) (*this)[i] -= q[i];
    return *this;
  }
  P &operator*=(const P q) {
    drep(i, n) {
      (*this)[i] *= q[0];
      rep2(j, 1, q.size()) if (j <= i) (*this)[i] += q[j] * (*this)[i-j];
    }
    return *this;
  }
  P &operator/=(const P q) {
    rep(i, n) {
      rep2(j, 1, q.size()) if (j <= i) (*this)[i] -= q[j] * (*this)[i-j];
      (*this)[i] /= q[0];
    }
    return *this;
  }
  P operator+(const P q) const { return P(*this) += q; }
  P operator-(const P q) const { return P(*this) -= q; }
  P operator*(const P q) const { return P(*this) *= q; }
  P operator/(const P q) const { return P(*this) /= q; }
  P &mul(map<int, T> q) {
    drep(i, n) {
      (*this)[i] *= q[0];
      for (auto &[j, b]: q) if (j > 0 && j <= i) (*this)[i] += b * (*this)[i-j];
    }
    return *this;
  }
  P &div(map<int, T> q={{0, 1}, {1, -1}}) {
    rep(i, n) {
      for (auto &[j, b]: q) if (j > 0 && j <= i) (*this)[i] -= b * (*this)[i-j];
      (*this)[i] /= q[0];
    }
    return *this;
  }
};



int main() {
  ll n, k; cin >> n >> k;

  Polynomial<mint> f(n+1);
  f[0] = 1;
  f[1] = -1;

  map<int, mint> q;
  q[0] = 1;
  q[1] = -1;

  rep(i, k) {
    int l, r; cin >> l >> r;
    q[l] -= 1;
    q[r+1] += 1;
  }

  auto g = f.div(q);

  mint ans = g[n-1];
  cout << ans << '\n';
}


Measured memory_bytes: 6368