#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e10;
const long long MOD = 1e9 + 7;
using Graph = vector<vector<long long>>;
using pll = pair<long long, long long>;
template <class T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
long long ceilll(long long a, long long b) { return (a + b - 1) / b; }
long long get_digit(long long a) {
  long long digit = 0;
  while (a != 0) {
    a /= 10;
    digit++;
  }
  return digit;
}
template <typename T>
void vecdbg(vector<T> &v) {
  for (long long i = 0; i < (v.size()); i++) {
    cout << v[i] << " ";
  }
  cout << "\n";
  ;
}
template <typename T>
void vecvecdbg(vector<vector<T>> &v) {
  for (long long i = 0; i < (v.size()); i++) {
    for (long long j = 0; j < (v[i].size()); j++) {
      cout << v[i][j] << " ";
    }
    cout << "\n";
    ;
  }
}
template <long long mod>
struct ModInt {
  long long x;
  ModInt() : x(0) {}
  ModInt(long long x) : x(x >= 0 ? x % mod : (mod - -x % 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 = (long long)x * p.x % mod;
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt &operator^=(long long p) {
    ModInt res = 1;
    for (; p; p >>= 1) {
      if (p & 1) res *= *this;
      *this *= *this;
    }
    return *this = res;
  }
  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; }
  ModInt operator^(long long 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; }
  explicit operator long long() const { return x; }
  ModInt &operator=(const long long p) {
    x = p;
    return *this;
  }
  ModInt inverse() const {
    long long a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      a -= t * b;
      std::swap(a, b);
      u -= t * v;
      std::swap(u, v);
    }
    return ModInt(u);
  }
  friend std::ostream &operator<<(std::ostream &stream, const ModInt<mod> &p) {
    return stream << p.x;
  }
  friend std::istream &operator>>(std::istream &stream, ModInt<mod> &a) {
    long long x;
    stream >> x;
    a = ModInt<mod>(x);
    return stream;
  }
};
template <long long mod>
struct MComb {
  using mint = ModInt<mod>;
  std::vector<mint> fact;
  std::vector<mint> inv;
  MComb(long long n) {
    fact = std::vector<mint>(n + 1, 1);
    for (long long i = 1; i <= n; i++) fact[i] = fact[i - 1] * mint(i);
    inv.resize(n + 1);
    inv[n] = fact[n] ^ (mod - 2);
    for (long long i = n; i--;) inv[i] = inv[i + 1] * mint(i + 1);
  }
  mint ncr(long long n, long r) { return fact[n] * inv[r] * inv[n - r]; }
  mint npr(long n, long r) { return fact[n] * inv[n - r]; }
  mint nhr(long n, long r) {
    assert(n + r - 1 < (long long)fact.size());
    return ncr(n + r - 1, r);
  }
};
template <long long mod>
struct MPow {
  using mint = ModInt<mod>;
  mint modpow(mint a, long long n) {
    mint res = 1;
    while (n > 0) {
      if (n & 1) {
        res = res * a;
      }
      a = a * a;
      n >>= 1;
    }
    return res;
  }
};
MComb<998244353> com(510000);
MPow<998244353> mpow;
ModInt<998244353> dp[200010];
ModInt<998244353> dp_sum[200010];
int main() {
  std::cout << std::fixed << std::setprecision(15);
  long long n, k;
  cin >> n >> k;
  vector<long long> vec;
  vector<pair<long long, long long>> pv;
  for (long long i = 0; i < (k); i++) {
    long long l, r;
    cin >> l >> r;
    pv.emplace_back(l, r);
  }
  sort(pv.begin(), pv.end());
  for (long long i = 0; i < (pv.size()); i++) {
    for (long long j = pv[i].first; j <= pv[i].second; j++) {
      vec.push_back(j);
    }
  }
  dp[1] = 1;
  dp_sum[1] = 1;
  for (long long i = 1; i < n + 1; i++) {
    for (long long j = 0; j < pv.size(); j++) {
      if (i - pv[j].first < 0) continue;
      if (i - pv[i].second < 1) {
        dp[i] += (dp_sum[i - pv[j].first] - dp_sum[0]);
      } else {
        dp[i] += (dp_sum[i - pv[j].first] - dp_sum[i - pv[j].second - 1]);
      }
    }
    dp_sum[i] = dp_sum[i - 1] + dp[i];
  }
  cout << dp[n] << endl;
}
