#include <bits/stdc++.h>

#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...) ((void)0)
#endif

template <typename T, typename U>
bool chmin(T &a, const U &b){
  return (a > b ? a = b, true : false);
}

template <typename T, typename U>
bool chmax(T &a, const U &b){
  return (a < b ? a = b, true : false);
}

template <typename T, size_t N, typename U>
void fill_array(T (&a)[N], const U &v){
  std::fill((U*)a, (U*)(a + N), v);
}

template <typename T, size_t N, size_t I = N>
auto make_vector(const std::array<int, N> &a, T value = T()){
  static_assert(I >= 1);
  static_assert(N >= 1);
  if constexpr (I == 1){
    return std::vector<T>(a[N - I], value);
  }else{
    return std::vector(a[N - I], make_vector<T, N, I - 1>(a, value));
  }
}

template <typename T>
std::ostream& operator<<(std::ostream &s, const std::vector<T> &a){
  for(auto it = a.begin(); it != a.end(); ++it){
    if(it != a.begin()) s << " ";
    s << *it;
  }
  return s;
}

template <typename T>
std::istream& operator>>(std::istream &s, std::vector<T> &a){
  for(auto &x : a) s >> x;
  return s;
}

namespace haar_lib {
  template <int32_t M>
  class modint {
    uint32_t val;

  public:
    constexpr static auto mod(){return M;}

    constexpr modint(): val(0){}
    constexpr modint(int64_t n){
      if(n >= M) val = n % M;
      else if(n < 0) val = n % M + M;
      else val = n;
    }

    constexpr auto& operator=(const modint &a){val = a.val; return *this;}
    constexpr auto& operator+=(const modint &a){
      if(val + a.val >= M) val = (uint64_t)val + a.val - M;
      else val += a.val;
      return *this;
    }
    constexpr auto& operator-=(const modint &a){
      if(val < a.val) val += M;
      val -= a.val;
      return *this;
    }
    constexpr auto& operator*=(const modint &a){
      val = (uint64_t)val * a.val % M;
      return *this;
    }
    constexpr auto& operator/=(const modint &a){
      val = (uint64_t)val * a.inv().val % M;
      return *this;
    }

    constexpr auto operator+(const modint &a) const {return modint(*this) += a;}
    constexpr auto operator-(const modint &a) const {return modint(*this) -= a;}
    constexpr auto operator*(const modint &a) const {return modint(*this) *= a;}
    constexpr auto operator/(const modint &a) const {return modint(*this) /= a;}

    constexpr bool operator==(const modint &a) const {return val == a.val;}
    constexpr bool operator!=(const modint &a) const {return val != a.val;}

    constexpr auto& operator++(){*this += 1; return *this;}
    constexpr auto& operator--(){*this -= 1; return *this;}

    constexpr auto operator++(int){auto t = *this; *this += 1; return t;}
    constexpr auto operator--(int){auto t = *this; *this -= 1; return t;}

    constexpr static modint pow(int64_t n, int64_t p){
      if(p < 0) return pow(n, -p).inv();

      int64_t ret = 1, e = n % M;
      for(; p; (e *= e) %= M, p >>= 1) if(p & 1) (ret *= e) %= M;
      return ret;
    }

    constexpr static modint inv(int64_t a){
      int64_t b = M, u = 1, v = 0;

      while(b){
        int64_t t = a / b;
        a -= t * b; std::swap(a, b);
        u -= t * v; std::swap(u, v);
      }

      u %= M;
      if(u < 0) u += M;

      return u;
    }

    constexpr static auto frac(int64_t a, int64_t b){return modint(a) / modint(b);}

    constexpr auto pow(int64_t p) const {return pow(val, p);}
    constexpr auto inv() const {return inv(val);}

    friend constexpr auto operator-(const modint &a){return modint(M - a.val);}

    friend constexpr auto operator+(int64_t a, const modint &b){return modint(a) + b;}
    friend constexpr auto operator-(int64_t a, const modint &b){return modint(a) - b;}
    friend constexpr auto operator*(int64_t a, const modint &b){return modint(a) * b;}
    friend constexpr auto operator/(int64_t a, const modint &b){return modint(a) / b;}

    friend std::istream& operator>>(std::istream &s, modint<M> &a){s >> a.val; return s;}
    friend std::ostream& operator<<(std::ostream &s, const modint<M> &a){s << a.val; return s;}

    template <int N>
    static auto div(){
      static auto value = inv(N);
      return value;
    }

    explicit operator int32_t() const noexcept {return val;}
    explicit operator int64_t() const noexcept {return val;}
  };
}

namespace haar_lib {
  template <typename Monoid>
  class dual_segment_tree {
    using value_type = typename Monoid::value_type;
    const static Monoid M;

    const int depth, size, hsize;
    std::vector<value_type> data;

    void propagate(int i){
      if(i < hsize){
        data[i << 1 | 0] = M(data[i], data[i << 1 | 0]);
        data[i << 1 | 1] = M(data[i], data[i << 1 | 1]);
        data[i] = M();
      }
    }

    void propagate_top_down(int i){
      std::vector<int> temp;
      while(i > 1){
        i >>= 1;
        temp.push_back(i);
      }

      for(auto it = temp.rbegin(); it != temp.rend(); ++it) propagate(*it);
    }

  public:
    dual_segment_tree(int n):
      depth(n > 1 ? 32 - __builtin_clz(n - 1) + 1 : 1),
      size(1 << depth), hsize(size / 2),
      data(size, M())
    {}

    void update(int l, int r, const value_type &x){
      propagate_top_down(l + hsize);
      propagate_top_down(r + hsize);

      int L = l + hsize;
      int R = r + hsize;

      while(L < R){
        if(R & 1) --R, data[R] = M(x, data[R]);
        if(L & 1) data[L] = M(x, data[L]), ++L;
        L >>= 1, R >>= 1;
      }
    }

    value_type operator[](int i){
      propagate_top_down(i + hsize);
      return data[i + hsize];
    }

    template <typename T>
    void init_with_vector(const std::vector<T> &a){
      data.assign(size, M());
      for(int i = 0; i < (int)a.size(); ++i) data[hsize + i] = a[i];
    }

    template <typename T>
    void init(const T &val){
      init_with_vector(std::vector<value_type>(hsize, val));
    }
  };
}



namespace haar_lib {
  template <typename T>
  struct sum_monoid {
    using value_type = T;
    value_type operator()() const {return 0;}
    value_type operator()(value_type a, value_type b) const {return a + b;}
  };
}



namespace haar_lib {}

namespace solver {
  using namespace haar_lib;

  constexpr int m1000000007 = 1000000007;
  constexpr int m998244353 = 998244353;

  void init(){
    std::cin.tie(0);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(12);
    std::cerr << std::fixed << std::setprecision(12);
    std::cin.exceptions(std::ios_base::failbit);
  }

  using mint = modint<m998244353>;

  void solve(){
    int N, K; std::cin >> N >> K;

    std::vector<int> L(K), R(K);
    for(int i = 0; i < K; ++i){
      std::cin >> L[i] >> R[i];
    }

    auto seg = dual_segment_tree<sum_monoid<mint>>(3 * N + 1);

    seg.update(1, 2, 1);

    for(int i = 1; i <= N; ++i){
      mint t = seg[i];

      for(int j = 0; j < K; ++j){
        seg.update(i + L[j], i + R[j] + 1, t);
      }
    }

    std::cout << seg[N] << "\n";
  }
}

int main(){
  solver::init();
  while(true){
    try{
      solver::solve();
    }catch(const std::istream::failure &e){
      break;
    }
  }
  return 0;
}


Measured memory_bytes: 11396