#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (ll i=a;i<b;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;}


namespace po167{
struct UFtree
{
	using _F=int;
	int _n;
	std::vector<_F> wei;
	std::vector<int> q;
	int component;
	UFtree(int n):_n(n),wei(n),component(n),par(n){
		for(int i=0;i<n;i++){
			wei[i]=1,par[i]=i;
		}
	}
	void intialize(){
		for(auto x:q){
			wei[root(x)]=1;
			par[x]=x;
		}
		component=(int)par.size();
		q={};
	}
	//根っこを返す
	int root(int a){
		assert(0<=a&&a<_n);
		if(a==par[a]) return a;
		return par[a]=root(par[a]);
	}
	//trueなら1,falseなら0
	int same(int a,int b){
		assert(0<=a&&a<_n);
		assert(0<=b&&b<_n);
		if(root(a)==root(b)) return 1;
		else return 0;
	}
	_F size(int a){
		return wei[root(a)];
	}
	//a,bが違う根っこの元なら結合する,結合したらtrueを返す
	bool unite(int a,int b){
		a=root(a),b=root(b);
		if(a==b) return false;
		if(wei[a]<wei[b]) std::swap(a,b);
		par[b]=a;
		q.push_back(b);
		wei[a]+=wei[b];
		component--;
		return true;
	}
	private:
	std::vector<int> par;
};
}
using po167::UFtree;

namespace po167{
struct combination{
	int upper;
	long long MOD;
	std::vector<long long> fact;
	std::vector<long long> rev;
	std::vector<long long> fact_rev;
	combination(int max,long long mod):upper(max),MOD(mod),fact(max+1),rev(max+1),fact_rev(max+1){
		for(long long i=0;i<=max;i++){
			if(i<2){
				fact[i]=1;
				fact_rev[i]=1;
				rev[i]=1;
				continue;
			}
			fact[i]=(fact[i-1]*i)%mod;
			rev[i]=mod-((mod/i)*rev[mod%i])%mod;
			fact_rev[i]=(fact_rev[i-1]*rev[i])%mod;
		}
	}
	long long Comb(int x,int y){
		assert(upper>=x);
		if (x<y||y<0||x<0) return 0;
		return (((fact_rev[y]*fact_rev[x-y])%MOD)*fact[x])%MOD;
	}
	long long P(int x,int y){
		assert(upper>=x);
		if (x<y||y<0||x<0) return 0;
		return (fact_rev[x-y]*fact[x])%MOD;
	}
};
}
using po167::combination;



void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,0,t) solve();
}

void solve(){
	ll N,Q;
	cin>>N>>Q;
	combination table(N+10,mod);
	ll v=1;
	if(N&1) N++,v=table.rev[(N+1)/2];
	vector<int> L(Q+1),R(Q+1);
	R[Q]=N;
	rep(i,0,Q){
		cin>>L[i]>>R[i];
		L[i]--;
		if((R[i]-L[i])&1) v=0;
	}
	UFtree T(Q+1);
	rep(i,0,Q+1) rep(j,0,Q+1){
		if(L[i]<L[j]&&R[j]<R[i]) continue;
		if(L[j]<L[i]&&R[i]<R[j]) continue;
		if(R[i]<L[j]||R[j]<L[i]) continue;
		T.unite(i,j);
	}
	vector<set<int>> s(Q+1);
	rep(i,0,Q+1){
		s[T.root(i)].insert(L[i]);
		s[T.root(i)].insert(R[i]);
	}
	auto C=[&](int a)->ll{
		if(a&1) return 0;
		return (table.Comb(a,a/2)*table.rev[a/2+1])%mod;
	};
	vector<int> p(Q+1);
	stack<int> st;
	ll ans=1;
	rep(i,0,N+1){
		rep(j,0,Q+1){
			if(s[j].count(i)){
				if(i==(*s[j].begin())) st.push(j);
				else{
					ans=(ans*C(p[j]))%mod;
					p[j]=0;
				}
				if(i==(*s[j].rbegin())) st.pop();
			}
		}
		if(i!=N) p[st.top()]++;
	}
	ans=(ans*table.fact[N/2])%mod;
	ans=(ans*table.fact[N/2])%mod;
	ans=(ans*v)%mod;
	cout<<ans<<"\n";
}