#line 1 "main_d.cpp"
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cstdint>
#include <cstdlib>
#include <cmath>
#include <complex>
#include <chrono>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>
#include <random>
#include <utility>
#include <limits>
#include <list>
#include <type_traits>

/* template start */

using i64=std::int_fast64_t;
using u64=std::uint_fast64_t;
 
#define rep(i, a, b) for (i64 i = (a); (i) < (b); (i)++)
#define all(i) i.begin(), i.end()

#ifdef LOCAL
#define debug(...) std::cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out(){std::cerr<<std::endl;}

template<typename Head,typename... Tail>
void debug_out(Head h,Tail... t){
  std::cerr<<" "<<h;
  if(sizeof...(t)>0)std::cout<<" :";
  debug_out(t...);
}
 
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, std::pair<T1, T2> pa) {
  return os << pa.first << " " << pa.second;
}
 
template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
  for (std::size_t i = 0; i < vec.size(); i++)os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  return os;
}
 
template<typename T1,typename T2>
inline bool chmax(T1& a,T2 b){return a<b && (a=b,true);}
 
template<typename T1,typename T2>
inline bool chmin(T1& a,T2 b){return a>b && (a=b,true);}

template<typename Num>
constexpr Num mypow(Num a, u64 b,Num id=1) {
  if(b==0)return id;
  Num x = id;
  while (b > 0) {
    if(b & 1)x*=a;
    a*=a;
    b >>= 1;
  }
  return x;
}

/* template end */

#line 2 "/home/imperi/cp-library/lib/utility/modint.hpp"

/*
  author:noshi91
  reference:https://noshi91.hatenablog.com/entry/2019/03/31/174006
            https://github.com/noshi91/Library/blob/master/other/modint.cpp

  1つめのmodintにoperator==,!=を追加したものです

  thx @noshi91!!
*/

#line 14 "/home/imperi/cp-library/lib/utility/modint.hpp"

template <std::uint_fast64_t Modulus>
class modint {
  using u64 = std::uint_fast64_t;

 public:
  u64 a;

  constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
  constexpr u64 &value() noexcept { return a; }
  constexpr const u64 &value() const noexcept { return a; }
  constexpr bool operator==(const modint rhs) const noexcept {
    return a == rhs.a;
  }
  constexpr bool operator!=(const modint rhs) const noexcept {
    return !(*this == rhs);
  }
  constexpr modint operator+(const modint rhs) const noexcept {
    return modint(*this) += rhs;
  }
  constexpr modint operator-(const modint rhs) const noexcept {
    return modint(*this) -= rhs;
  }
  constexpr modint operator*(const modint rhs) const noexcept {
    return modint(*this) *= rhs;
  }
  constexpr modint operator/(const modint rhs) const noexcept {
    return modint(*this) /= rhs;
  }
  constexpr modint &operator+=(const modint rhs) noexcept {
    a += rhs.a;
    if (a >= Modulus) {
      a -= Modulus;
    }
    return *this;
  }
  constexpr modint &operator-=(const modint rhs) noexcept {
    if (a < rhs.a) {
      a += Modulus;
    }
    a -= rhs.a;
    return *this;
  }
  constexpr modint &operator*=(const modint rhs) noexcept {
    a = a * rhs.a % Modulus;
    return *this;
  }
  constexpr modint &operator/=(modint rhs) noexcept {
    u64 exp = Modulus - 2;
    while (exp) {
      if (exp % 2) {
        *this *= rhs;
      }
      rhs *= rhs;
      exp /= 2;
    }
    return *this;
  }
};
#line 2 "/home/imperi/cp-library/lib/SegmentTree/SegmentTree.hpp"

#line 5 "/home/imperi/cp-library/lib/SegmentTree/SegmentTree.hpp"

// Monoid
// type value_t
// static var id
// static (value_t,value_t)->value_t op

template <typename Monoid>
class SegmentTree {
 public:
  using value_t = typename Monoid::value_t;
  using size_t = std::size_t;

 private:
  size_t n, n0;
  std::vector<value_t> dat;

 public:
  SegmentTree(size_t n_) : n(n_) {
    assert(n_ > 0);
    n0 = 1;
    while (n0 < n) n0 <<= 1;
    dat = std::vector<value_t>(2 * n0 - 1, Monoid::id);
  }

  SegmentTree(const std::vector<value_t>& tmp) : n(tmp.size()) {
    assert(n > 0);
    n0 = 1;
    while (n0 < n) n0 <<= 1;
    dat = std::vector<value_t>(2 * n0 - 1, Monoid::id);
    for (size_t i = 0; i < n; i++) dat[i + n0 - 1] = tmp[i];
    for (long long i = n0 - 2; i >= 0; i--)
      dat[i] = Monoid::op(dat[2 * i + 1], dat[2 * i + 2]);
  }

  void update(size_t i, value_t val, bool change) {
    assert(0 <= i && i < n);
    std::size_t now = i + n0 - 1;
    if (change)
      dat[now] = val;
    else
      dat[now] = Monoid::op(dat[now], val);

    while (now > 0) {
      now = (now - 1) >> 1;
      dat[now] = Monoid::op(dat[2 * now + 1], dat[2 * now + 2]);
    }
  }

  value_t fold(size_t a, size_t b) {
    assert(0 <= a && a <= b && b <= n);
    value_t rval = Monoid::id, lval = Monoid::id;
    size_t l = a + n0 - 1, r = b + n0 - 1;
    for (; l < r; l >>= 1, r >>= 1) {
      if (!(r & 1)) {
        r--;
        rval = Monoid::op(dat[r], rval);
      }
      if (!(l & 1)) {
        lval = Monoid::op(lval, dat[l]);
        l++;
      }
    }

    return Monoid::op(lval, rval);
  }
};
#line 86 "main_d.cpp"

constexpr u64 MOD=998244353;
using mint=modint<MOD>;

struct Monoid{
  using value_t = mint;
  static constexpr value_t id=0;
  static constexpr value_t op(value_t a,value_t b){
    return a+b;
  }
};

int main() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
  
  i64 n,k;
  std::cin>>n>>k;

  SegmentTree<Monoid> seg(n);
  seg.update(n-1,1,false);

  std::vector<i64> l(k),r(k);
  rep(i,0,k){
    std::cin>>l[i]>>r[i];
    r[i]++;
  }

  for(i64 i=n-2;i>=0;i--){
    mint val=0;
    rep(j,0,k){
      if(i+l[j]<n)val+=seg.fold(i+l[j],std::min(i+r[j],n));
    }
    seg.update(i,val,true);
  }

  std::cout<<seg.fold(0,1).value()<<"\n";

  return 0;
}


Measured memory_bytes: 7428