#include <bits/stdc++.h>
using namespace std;
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
const int mod = 998244353;
template <int mod>
struct ModInt {
  int x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }
  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while (n > 0) {
      if (n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int get_mod() { return mod; }
};
using mi = ModInt<mod>;
template <typename Monoid>
struct SegmentTree {
  using F = function<Monoid(Monoid, Monoid)>;
  int sz;
  vector<Monoid> seg;
  const F f;
  const Monoid M1;
  SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while (sz < n) sz <<= 1;
    seg.assign(2 * sz, M1);
  }
  void set(int k, const Monoid &x) { seg[k + sz] = x; }
  void build() {
    for (int k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
  void update(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while (k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
  Monoid query(int a, int b) {
    Monoid L = M1, R = M1;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) L = f(L, seg[a++]);
      if (b & 1) R = f(seg[--b], R);
    }
    return f(L, R);
  }
  Monoid operator[](const int &k) const { return seg[k + sz]; }
  template <typename C>
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]);
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }
  template <typename C>
  int find_first(int a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, seg[1]))) return find_subtree(1, check, L, false);
      return -1;
    }
    int b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, seg[a]);
        if (check(nxt)) return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }
  template <typename C>
  int find_last(int b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(seg[1], R))) return find_subtree(1, check, R, true);
      return -1;
    }
    int a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(seg[--b], R);
        if (check(nxt)) return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};
void solve() {
  int N, K;
  cin >> N >> K;
  SegmentTree<mi> seg(
      N + 1, [](mi a, mi b) { return a + b; }, mi(0));
  vector<pair<int, int>> kukan(K);
  for (int i = 0, i_len = (K); i < i_len; ++i) {
    int l, r;
    cin >> l >> r;
    l;
    r;
    kukan[i] = make_pair(l, r);
  }
  seg.update(0, mi(0));
  seg.update(1, mi(1));
  for (int i = (2); i < (N + 1); ++i) {
    mi ptn(0);
    for (int j = 0, j_len = (K); j < j_len; ++j) {
      auto [l, r] = kukan[j];
      int fromr = i - l;
      int froml = i - r;
      if (froml > fromr || fromr < 1) continue;
      ptn += seg.query(froml, fromr + 1);
    }
    seg.update(i, ptn);
  }
  cout << seg[N] << "\n";
}
void solve2() {
  int N, K;
  cin >> N >> K;
  SegmentTree<int> seg(
      N + 1, [](int a, int b) { return (a + b) % mod; }, INT_MAX);
  vector<pair<int, int>> kukan(K);
  for (int i = 0, i_len = (K); i < i_len; ++i) {
    int l, r;
    cin >> l >> r;
    l;
    r;
    kukan[i] = make_pair(l, r);
  }
  seg.update(0, int(0));
  seg.update(1, int(1));
  for (int i = (2); i < (N + 1); ++i) {
    mi ptn(0);
    cerr << "dp[" << i << "] = "
         << "\n";
    for (int j = 0, j_len = (K); j < j_len; ++j) {
      auto [l, r] = kukan[j];
      int fromr = i - l;
      int froml = i - r;
      cerr << "+dp[" << froml << "] +...+ dp[" << fromr << "] "
           << "\n";
      if (froml > fromr || fromr < 1) continue;
      ptn += mi(seg.query(froml, fromr + 1));
    }
    seg.update(i, ptn.x);
    cerr << "= " << ptn.x << "\n";
  }
  cout << seg[N] << "\n";
}
int main() {
  solve();
  return 0;
}
