
//#pragma GCC optimize("03,unroll-loops")
//#pragma GCC target("avx,avx2,fma")

#include<bits/stdc++.h>
typedef long long ll;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pb           push_back
#define ff           first
#define ss           second
#define gcd(a, b)    __gcd(a, b)
#define lcm(a, b)    ((a)*((b)/gcd(a,b)))
#define all(v)       v.begin(),v.end()
#define rall(v)      v.rbegin(),v.rend()
#define lllim        2147483648
#define Pi           2*acos(0.0)
#define pii          pair<int,int>
#define pll 	     pair<ll,ll>
#define mem(a,b)     memset(a, b, sizeof(a))
#define fill_(a,b)   fill(a,a+n,b);
#define mod          1000000007
#define fast_cin     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define filein       freopen("input.txt","r", stdin)
#define D(x)         cerr << __LINE__ << ": " << #x << " = " << (x) << '\n'
#define case		 int t,cas=1;cin>>t;while(t--)
#define rep(i,a,n)   for(int i=a;i<n;i++)
#define rev(i,n,a)   for(int i=n;i>=a;i--)
#define sim 		 template<class T

/*------------------------------Graph Moves----------------------------*/
//const int fx[]= {+1,-1,+0,+0};
//const int fy[]= {+0,+0,+1,-1};
//const int fx[]= {+0,+0,+1,-1,-1,+1,-1,+1};  // Kings Move
//const int fy[]= {-1,+1,+0,+0,+1,+1,-1,-1}; // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*---------------------------------------------------------------------*/

sim > void ckmin(T& a, const T& b) {
    a= b < a? b:a;
}
sim > void ckmax(T& a, const T& b) {
    a= b > a? b:a;
}

///.............................input.................................///
sim > void readvec( std::vector<T>& v, const int n) {
    rep(i,0,n) {
        T p;
        std::cin>>p;
        v.pb(p);
    }
}
///...........................input end...............................///


using namespace std;
using namespace __gnu_pbds;

const int maxn=200005;

ll dp[maxn];
ll n,k;
vector<int > v;


ll func(ll idx)
{
	if(idx>n) return 0;
	if(idx==n) return 1;
	
	ll &ret =dp[idx];
	
	if(ret!=-1){
		return ret;
	}
	
	ret =0;
	
	for(int i=0;i<v.size();i++)
	{
		ret+=(func(idx+v[i]));
	}
	
	return ret%998244353;
	
}


void solve()
{
	cin>>n>>k;
	
	ll cnt[n+3]={0};
	
	for(int i=0;i<k;i++)
	{
		int l,r;
		cin>>l>>r;
		cnt[l]+=1;
		cnt[r+1]-=1;
	}
	
	for(int i=1;i<n+2;i++)
	{
		cnt[i]+=cnt[i-1];
	}
	
	for(int i=1;i<=n;i++)
	{
		//cout<<cnt[i]<<endl;
		if(cnt[i]) v.pb(i);
	}
	
	//sort(all(v));
	
	
	mem(dp,-1);
	ll ans=func(1);
	
	cout<<ans<<endl;

 

}


int main()
{
    fast_cin;


    //case
    {
        //  cout<<"Case "<<cas++<<": ";
        solve();
    }

    return 0;
}
