#pragma GCC optimize ("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define all(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(typename remove_const<typename remove_reference<decltype(l)>::type>::type cnt={};(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const long long MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename T> inline T& chmax(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& chmin(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T, typename Random = decltype(randdev), typename enable_if<is_integral<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_int_distribution<T>(l, h)(rand); }
template<typename T, typename Random = decltype(randdev), typename enable_if<is_floating_point<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_real_distribution<T>(l, h)(rand); }

template <typename I>
struct MyRangeFormat{ I b,e; MyRangeFormat(I _b, I _e):b(_b),e(_e){} };
template<typename I>
static ostream& operator<<(ostream& o, const MyRangeFormat<I>& f) {
  o << "[ "; iterate(i,f.b,f.e) o<<*i<<' ';
  return o << ']';
}
template <typename I>
struct MyMatrixFormat{
  const I& p; long long n, m;
  MyMatrixFormat(const I& _p, long long _n, long long _m):p(_p),n(_n),m(_m){}
};
template<typename I>
static ostream& operator<<(ostream& o, const MyMatrixFormat<I>& f) {
  o<<'\n';
  repeat(i,(f.n)) {
    repeat(j,f.m) o<<f.p[i][j]<<' ';
    o<<'\n';
  }
  return o;
}
struct LOG_t { ~LOG_t() { cout << endl; } };
#define LOG (LOG_t(),cout<<'L'<<__LINE__<<": ")
#define FMTA(m,w) (MyRangeFormat<decltype(m+0)>(m,m+w))
#define FMTR(b,e) (MyRangeFormat<decltype(e)>(b,e))
#define FMTV(v) FMTR(v.begin(),v.end())
#define FMTM(m,h,w) (MyMatrixFormat<decltype(m+0)>(m,h,w))

#if defined(_WIN32) || defined(_WIN64)
#define getc_x _getc_nolock
#define putc_x _putc_nolock
#elif defined(__GNUC__)
#define getc_x getc_unlocked
#define putc_x putc_unlocked
#else
#define getc_x getc
#define putc_x putc
#endif
class MaiScanner {
  FILE* fp_;
  constexpr bool isvisiblechar(char c) noexcept { return (0x21<=(c)&&(c)<=0x7E); }
public:
  inline MaiScanner(FILE* fp):fp_(fp){}
  template<typename T> void input_integer(T& var) noexcept {
    var = 0; T sign = 1;
    int cc = getc_x(fp_);
    for (; cc < '0' || '9' < cc; cc = getc_x(fp_))
      if (cc == '-') sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_))
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() noexcept { return getc_x(fp_); }
  template<typename T, typename enable_if<is_integral<T>::value, nullptr_t>::type = nullptr>
  inline MaiScanner& operator>>(T& var) noexcept { input_integer<T>(var); return *this; }
  inline MaiScanner& operator>>(string& var) {
    int cc = getc_x(fp_);
    for (; !isvisiblechar(cc); cc = getc_x(fp_));
    for (; isvisiblechar(cc); cc = getc_x(fp_))
      var.push_back(cc);
    return *this;
  }
  template<typename IT> inline void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
};
class MaiPrinter {
  FILE* fp_;
public:
  inline MaiPrinter(FILE* fp):fp_(fp){}
  template<typename T>
  void output_integer(T var) noexcept {
    if (var == 0) { putc_x('0', fp_); return; }
    if (var < 0)
      putc_x('-', fp_),
      var = -var;
    char stack[32]; int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10),
      var /= 10;
    while (stack_p)
      putc_x(stack[--stack_p], fp_);
  }
  inline MaiPrinter& operator<<(char c) noexcept { putc_x(c, fp_); return *this; }
  template<typename T, typename enable_if<is_integral<T>::value, nullptr_t>::type = nullptr>
  inline MaiPrinter& operator<<(T var) noexcept { output_integer<T>(var); return *this; }
  inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putc_x(*(str_p++), fp_); return *this; }
  inline MaiPrinter& operator<<(const string& str) {
    const char* p = str.c_str();
    const char* l = p + str.size();
    while (p < l) putc_x(*p++, fp_);
    return *this;
  }
  template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; }
};
MaiScanner scanner(stdin);
MaiPrinter printer(stdout);

template <typename T = long long>
class Bitree {
  const int size_;
  vector<T> data_;
  static int nlz(uint32_t x) {
    union {
      uint32_t i;
      float f;
    } data;
    data.f = (float)x + 0.5;
    return 158 - (data.i >> 23);
  }

 public:
  Bitree(int size_) : size_(size_), data_(size_ + 1) {}

  // 1..rの範囲の値の和を求める．
  T sum(int r) const {
    T s = 0;
    while (r) {
      s += data_[r];
      r -= r & -r;  //  r&-r と書くことで最下のビットを得る
    }
    return s;
  }
  // l..rの範囲の値の和を求める
  inline T sum(int l, int r) const { return sum(r) - sum(l - 1); }
  // i番目の値を求める(1index)
  T get(int i) const {
    int j = i - 1;
    T s = 0;
    while (i != j) {
      s += data_[i] - data_[j];
      i -= i & -i;
      j -= j & -j;
    }
    return s;
  }
  // idxの要素の値をval増やす
  void add(int idx, T val) {
    while (idx <= size_) {
      data_[idx] += val;
      idx += idx & -idx;
    }
  }
  // sum(i)がvalを超える最初のiを返す
  // get(j)<0となるjが存在すると正しく動作しない
  int upper_bound(T val) const {
    int li = 1 << (31 - nlz(size_));
    int p = 0;
    T d = 0;
    while (li && p < size_) {
      T k = data_[p | li];
      if (!(val < d + k))
        p |= li, d += k;
      li >>= 1;
    }
    if (p > size_)
      p = size_;
    return p + 1;
  }
  // sum(i)がval以上である最初のiを返す
  // get(j)<0となるjが存在すると正しく動作しない
  int lower_bound(T val) const {
    int li = 1 << (31 - nlz(size_));
    int p = 0;
    T d = 0;
    while (li && p < size_) {
      T k = data_[p | li];
      if (d + k < val)
        p |= li, d += k;
      li >>= 1;
    }
    if (p > size_)
      p = size_;
    return p + 1;
  }
};

class llmod {
 private:
  using value_type = long long;
  value_type val_;
  // inline ll cut(ll v) const { return ((v%MOD) + MOD) % MOD; } // safe
 public:
  static const value_type MOD = 998244353;  // <=

  llmod() : val_(0) {}
  llmod(value_type num) : val_(((num % MOD) + MOD) % MOD) {}

  inline operator value_type() const { return val_; }
  inline value_type operator*() const { return val_; }
  inline llmod& operator=(const llmod& lm) {
    val_ = lm.val_;
    return *this;
  }
  inline llmod& operator=(value_type v) {
    val_ = (v) % MOD;
    return *this;
  }

  inline llmod& operator+=(value_type v) {
    val_ = (val_ + v) % MOD;
    return *this;
  }
  inline llmod& operator+=(const llmod& l) {
    val_ = (val_ + l.val_) % MOD;
    return *this;
  }
  inline llmod& operator-=(value_type v) {
    val_ = (val_ - v + MOD) % MOD;
    return *this;
  }
  inline llmod& operator-=(const llmod& l) {
    val_ = (val_ - l.val_ + MOD) % MOD;
    return *this;
  }
  inline llmod& operator*=(value_type v) {
    val_ = (val_ * v) % MOD;
    return *this;
  }
  inline llmod& operator*=(const llmod& l) {
    val_ = (val_ * l.val_) % MOD;
    return *this;
  }
  inline llmod& operator++() {
    val_ = (val_ + 1) % MOD;
    return *this;
  }
  inline llmod operator++(int) {
    llmod t = *this;
    val_ = (val_ + 1) % MOD;
    return t;
  }
  inline llmod& justify() {
    val_ = ((val_ % MOD) + MOD) % MOD;
    return *this;
  }
  friend llmod pow(llmod, long long);
};
inline std::ostream& operator<<(std::ostream& os, const llmod& l) {
  os << *l;
  return os;
}

inline llmod operator+(llmod t, const llmod& r) {
  return t += r;
}
inline llmod operator-(llmod t, const llmod& r) {
  return t -= r;
}
inline llmod operator*(llmod t, const llmod& r) {
  return t *= r;
}
inline llmod operator*(llmod t, ll r) {
  return t *= r;
}

// MEMO : 逆元...pow(n,MD-2)
llmod pow(llmod x, long long p) {
  llmod::value_type y = 1;
  llmod::value_type xval = x.justify();
  while (0 < p) {
    if (p & 1)
      y = (xval * y) % llmod::MOD;
    xval = (xval * xval) % llmod::MOD;
    p >>= 1;
  }
  return llmod(y);
}

inline llmod& operator/=(llmod& l, const llmod& r) {
  return l *= pow(r, llmod::MOD - 2);
}

template <typename T>
// using T = ll;
class SegmentTree {
 public:
  struct IdxVal {
    int index;
    T value;
    inline IdxVal(int _i = 0, const T& _v = T()) : index(_i), value(_v) {}
    inline void set(int i, const T& v) {
      index = i;
      value = v;
    }
    inline bool operator<(const T& t) const { return value < t; }
    inline bool operator==(const T& t) const { return value == t; }
    inline bool operator<(const IdxVal& iv) const {
      return value < iv.value || (value == iv.value && index < iv.index);
    }
    inline bool operator==(const IdxVal& iv) const {
      return index == iv.index && value == iv.value;
    }
  };

  enum struct Cmd { None, Add, Flat };

  struct Node {
    T sum, lazyValue;
    IdxVal max;
    Cmd lazyType;
  };

 private:
  const int size_;
  vector<T> leaf_data_;
  vector<Node> node_data_;
  T* leaf_;
  Node* node_;

  void _resize() {
    leaf_data_.resize(size_);
    node_data_.resize(size_ - 1);

    leaf_ = &leaf_data_[0];
    node_ = &node_data_[0] - 1;
  }

  void _init() {
    for (int i = size_ - 1; 0 < i; --i) {
      int c = i << 1;
      if (size_ <= c)
        node_[i].max.set(c - size_, leaf_[c - size_]);
      else
        node_[i].max = node_[c].max;
      node_[i].lazyType = Cmd::None;
      node_[i].sum = node_[i].lazyValue = 0;
    }
  }

 public:
  inline void fill(T val) {
    std::fill(leaf_data_.begin(), leaf_data_.end(), val);
    _init();
  }

  SegmentTree(int _n)
      : size_([](int _n) {
          int s = 8;
          while (s < _n)
            s <<= 1;
          return s;
        }(_n)) {
    _resize();
    _init();
  }
  SegmentTree(int _n, const T& _fillVal)
      : size_([](int _n) {
          int s = 8;
          while (s < _n)
            s <<= 1;
          return s;
        }(_n)) {
    _resize();
    fill(_fillVal);
  }

 private:
  // lazyを適応する(子を呼ぶ前に呼ぶ)
  // width: ptrが担当するnodeの範囲の大きさ(ptr = 1 ならば size_)
  inline void _applyDown(int ptr, int width) {
    width >>= 1;
    // if (size_ <= ptr) return;
    if (node_[ptr].lazyType == Cmd::Add) {
      int c = ptr << 1;

      if (size_ <= c) {
        leaf_[c - size_] += node_[ptr].lazyValue;
        leaf_[c + 1 - size_] += node_[ptr].lazyValue;
      } else {
        node_[c].sum += node_[ptr].lazyValue * width;
        node_[c].max.value += node_[ptr].lazyValue;
        node_[c].lazyValue += node_[ptr].lazyValue;
        if (node_[c].lazyType == Cmd::None)
          node_[c].lazyType = Cmd::Add;

        node_[c + 1].sum += node_[ptr].lazyValue * width;
        node_[c + 1].max.value += node_[ptr].lazyValue;
        node_[c + 1].lazyValue += node_[ptr].lazyValue;
        if (node_[c + 1].lazyType == Cmd::None)
          node_[c + 1].lazyType = Cmd::Add;
      }

      node_[ptr].lazyType = Cmd::None;
      node_[ptr].lazyValue = 0;
    } else if (node_[ptr].lazyType == Cmd::Flat) {
      node_[ptr].lazyType = Cmd::None;
      int c = ptr << 1;

      if (size_ <= c) {
        leaf_[c - size_] = node_[ptr].lazyValue;
        leaf_[c + 1 - size_] = node_[ptr].lazyValue;
      } else {
        node_[c].sum = node_[ptr].lazyValue * width;
        node_[c].max.value = node_[ptr].lazyValue;
        node_[c].lazyValue = node_[ptr].lazyValue;
        node_[c].lazyType = Cmd::Flat;

        node_[c + 1].sum = node_[ptr].lazyValue * width;
        node_[c + 1].max.value = node_[ptr].lazyValue;
        node_[c + 1].lazyValue = node_[ptr].lazyValue;
        node_[c + 1].lazyType = Cmd::Flat;
      }

      node_[ptr].lazyType = Cmd::None;
      node_[ptr].lazyValue = 0;
    }
  }

  // lazyを適応する(子を呼んだ後に呼ぶ)
  inline void _applyUp(int ptr) {
    if (size_ <= ptr << 1) {
      int i = (ptr << 1) - size_;
      if (leaf_[i] < leaf_[i + 1])
        node_[ptr].max.set(i + 1, leaf_[i + 1]);
      else
        node_[ptr].max.set(i, leaf_[i]);
      node_[ptr].sum = leaf_[i] + leaf_[i + 1];
    } else {
      if (node_[(ptr << 1)].max.value < node_[(ptr << 1) + 1].max.value)
        node_[ptr].max = node_[(ptr << 1) + 1].max;
      else
        node_[ptr].max = node_[(ptr << 1)].max;
      node_[ptr].sum = node_[ptr << 1].sum + node_[(ptr << 1) + 1].sum;
    }
  }

  // _downward_applyDown(ptr1): leaf[ptr1]の値を正しくする．
  void _downward_applyDown(int ptr1, int width = 1) {
    if (1 < ptr1)
      _downward_applyDown(ptr1 >> 1, width << 1);
    _applyDown(ptr1, width);
  }

  void _setValueRange(int begin, int end, T val, int ptr, int rangebegin, int rangeend) {
    if (rangeend <= begin || end <= rangebegin)
      return;  // note:範囲外
    if (begin <= rangebegin && rangeend <= end) {
      if (size_ <= ptr) {
        leaf_[rangebegin] = val;
      } else {
        node_[ptr].sum = val * (rangeend - rangebegin);
        node_[ptr].max.value = val;
        node_[ptr].lazyType = Cmd::Flat;
        node_[ptr].lazyValue = val;
      }
      return;
    }

    _applyDown(ptr, rangeend - rangebegin);

    _setValueRange(begin, end, val, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
    _setValueRange(begin, end, val, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

    _applyUp(ptr);
  }

  void _addValueRange(int begin, int end, T val, int ptr, int rangebegin, int rangeend) {
    if (rangeend <= begin || end <= rangebegin)
      return;  // note:範囲外
    if (begin <= rangebegin && rangeend <= end) {
      if (size_ <= ptr) {
        leaf_[rangebegin] += val;
      } else {
        node_[ptr].sum += val * (rangeend - rangebegin);
        node_[ptr].max.value += val;
        node_[ptr].lazyValue += val;
        if (node_[ptr].lazyType == Cmd::None)
          node_[ptr].lazyType = Cmd::Add;
      }
      return;
    }

    _applyDown(ptr, rangeend - rangebegin);

    _addValueRange(begin, end, val, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
    _addValueRange(begin, end, val, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

    _applyUp(ptr);
  }

  T _getSumRange(int begin, int end, int ptr, int rangebegin, int rangeend) {
    if (rangeend <= begin || end <= rangebegin)
      return 0;  // note:範囲外
    if (begin <= rangebegin && rangeend <= end) {
      if (size_ <= ptr)
        return leaf_[rangebegin];
      else
        return node_[ptr].sum;
    }

    _applyDown(ptr, rangeend - rangebegin);

    return _getSumRange(begin, end, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1) +
           _getSumRange(begin, end, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);
  }

  IdxVal _getMaxRange(int begin, int end, int ptr, int rangebegin, int rangeend) {
    if (rangeend <= begin || end <= rangebegin)
      return IdxVal(-1);  // note:範囲外
    if (begin <= rangebegin && rangeend <= end) {
      if (size_ <= ptr)
        return IdxVal(rangebegin, leaf_[rangebegin]);
      else
        return node_[ptr].max;
    }

    _applyDown(ptr, rangeend - rangebegin);

    auto l = _getMaxRange(begin, end, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
    auto r = _getMaxRange(begin, end, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

    if (l.index == -1)
      return move(r);
    if (r.index == -1)
      return move(l);
    return l.value < r.value ? move(r) : move(l);
  }

 public:
  // [index] の値を求める
  inline T getValue(int index) {
    _downward_applyDown((index + size_) >> 1);
    return leaf_[index];
  }

  // [index] の値を書き換える
  inline void setValue(int index, T val) {
    _downward_applyDown((index + size_) >> 1);
    T diff = val - leaf_[index];
    leaf_[index] = val;

    for (int ptr = (index + size_); 1 < ptr;) {
      ptr >>= 1;
      node_[ptr].sum -= diff;
      _applyUp(ptr);
    }
  }

  // [index] の値に加算する
  inline void addValue(int index, T val) {
    _downward_applyDown((index + size_) >> 1);
    leaf_[index] += val;

    for (int ptr = (index + size_); 1 < ptr;) {
      ptr >>= 1;
      node_[ptr].sum += val;
      _applyUp(ptr);
    }
  }

  // 区間[begin,end)全てにvalをセットする
  inline void setValueRange(int begin, int end, T val) {
    _setValueRange(begin, end, val, 1, 0, size_);
  }

  // 区間[begin,end)に一様にvalを加算する
  inline void addValueRange(int begin, int end, T val) {
    _addValueRange(begin, end, val, 1, 0, size_);
  }

  // 区間[begin,end)の和を求める
  inline T getSumRange(int begin, int end) { return _getSumRange(begin, end, 1, 0, size_); }

  // 区間[begin,end)の最大値とその位置を求める
  inline IdxVal getMaxRange(int begin, int end) { return _getMaxRange(begin, end, 1, 0, size_); }
};


//

int N, K;
vector<pair<int, int>> LR;

//




int main() {
  scanner >> N >> K;
  
  repeat(i, K) {
    int l, r; scanner >> l >> r;
    LR.emplace_back(l, r);
  }
  
  
  SegmentTree<llmod> segt(N+2);
  segt.setValue(0, 1);
  
  repeat(i, N) {
    auto c = segt.getValue(i);
    for (auto lr : LR) {
      int l = min(N+1, i + lr.first);
      int r = min(N+1, i + lr.second);
      // if (l >= N+1) continue;
      segt.addValueRange(l, r+1, c);
      // repeat(i, N+1) cout << segt.getValue(i) << ' '; cout << endl;
    }
  }
  
  cout << segt.getValue(N-1) << endl;
  
  return 0;
}


Measured memory_bytes: 15600