#include <bits/stdc++.h>
// #include "atcoder/all"
// #define popcount __builtin_popcount
using namespace std;
// using namespace atcoder;
#define FOR(i,o,n) for(long long i = o;i<n;i++)
#define oneforall ios::sync_with_stdio(false);cin.tie(0);
#define all(v) (v).begin(),(v).end()
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define int long long 
const long long inf=1e18;
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
typedef vector<int> vi;
typedef vector<long long> vl;
typedef long long ll;
typedef vector<pair<long, long > > vpll;
typedef vector<pair<int, int > > vpii;
#define FORR(x,arr) for(auto& x:arr)
#define ZERO(a) memset(a,0,sizeof(a))



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 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;
  }
};


//3111111111111111111111111111111

	void solve(){
		

		using mint = modint<998244353>;
		ini(n);
		ini(k);
		set<int> tmp;
		FOR(i,0,k){
			ini(x,x1);
			FOR(i,x,x1+1){
			  tmp.insert(i);
			}
		}
    int dp[311111];
    ZERO(dp);
    dp[0] = 1;
    FOR(i,0,n){
      if(dp[i]>0){
        for(auto x:tmp){
          if(x+i<=n){
            dp[i+x]+=dp[i];
            dp[i+x]%=998244353;
          }
        }
      }
    }
    out(dp[n-1]);

		
		
			
			
			


				
		


		
		
		
		

		


		
		
	}



	



















int32_t main() {
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall 
	oneforall

	solve();
	


	return 0;
}
