#include<iostream>
#include<vector>
#include<algorithm>
#include<atcoder/modint>
using namespace std;
using mint=atcoder::modint998244353;
#include<vector>
template<typename T>
struct combination{
	vector<T>fac,ifac;
	combination(size_t N=0):fac(1,1),ifac(1,1)
	{
		make_table(N);
	}
	void make_table(size_t N)
	{
		if(fac.size()>N)return;
		size_t now=fac.size();
		N=max(N,now*2);
		fac.resize(N+1);
		ifac.resize(N+1);
		for(size_t i=now;i<=N;i++)fac[i]=fac[i-1]*i;
		ifac[N]=1/fac[N];
		for(size_t i=N;i-->now;)ifac[i]=ifac[i+1]*(i+1);
	}
	T factorial(size_t n)
	{
		make_table(n);
		return fac[n];
	}
	T invfac(size_t n)
	{
		make_table(n);
		return ifac[n];
	}
	T P(size_t n,size_t k)
	{
		if(n<k)return 0;
		make_table(n);
		return fac[n]*ifac[n-k];
	}
	T C(size_t n,size_t k)
	{
		if(n<k)return 0;
		make_table(n);
		return fac[n]*ifac[n-k]*ifac[k];
	}
	T H(size_t n,size_t k)
	{
		if(n==0)return k==0?1:0;
		return C(n-1+k,k);
	}
};
combination<mint>C;
int N,Q;
main()
{
	cin>>N>>Q;
	if(N%2==1)N++;
	vector<pair<int,int> >LR;
	LR.push_back(make_pair(0,Q));
	LR.push_back(make_pair(N,~Q));
	for(int i=0;i<Q;i++)
	{
		int l,r;cin>>l>>r;
		l--;
		if((r-l)%2!=0)
		{
			cout<<0<<endl;
			return 0;
		}
		LR.push_back(make_pair(l,i));
		LR.push_back(make_pair(r,~i));
	}
	sort(LR.begin(),LR.end());
	vector<int>G;
	vector<pair<int,int> >S;
	for(pair<int,int>p:LR)
	{
		if(p.second>=0)S.push_back(p);
		else
		{
			int del=0;
			bool fn=false;
			for(int i=S.size();i--;)
			{
				if(!fn)
				{
					int t=p.first-S[i].first-del;
					if(t>0)G.push_back(t);
					del+=t;
				}
				if(S[i].second==~p.second)
				{
					S.erase(S.begin()+i);
					fn=true;
				}
				else S[i].first+=del;
			}
		}
	}
	mint ans=1;
	for(int t:G)ans*=C.C(t,t/2)/(t/2+1);
	ans*=C.factorial(N/2).pow(2);
	cout<<ans.val()<<endl;
}