#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ff first
#define ss second
#define endl "\n"
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x.size())
int powmod(int a,int l, int md){a%=md; int res=1;while(l){if(l&1)res=res*a%md;l/=2;a=a*a%md;}return res;}
int binpow(int a,int l){int res=1;while(l){if(l&1)res=res*a;l/=2;a=a*a;}return res;}
int invmod(int a, int md){return powmod(a,md-2,md);}
typedef long long ll; typedef unsigned long long ull; typedef long double ld;
typedef vector<int> vi; typedef pair<int, int> ii; typedef vector< ii > vii;
#define pb push_back
int __set(int b, int i) {return b|(1LL<<i);} //set ith bit
int __unset(int b, int i) {return b&(~(1UL<<i));}
int __check(int b, int i) {return b&(1LL<<i);} //returns 0 if ith bit is 0
int mulmod(int a, int b, int md) {return (((a%md)*(b%md))%md+md)%md;}
int addmod(int a, int b, int md) {return ((a%md+b%md)%md+md)%md;}
int submod(int a, int b, int md) {return (((a%md-b%md)%md)+md)%md;}
int divmod(int a, int b, int md) {return mulmod(a, powmod(b, md-2, md), md);} //if md is prime;
const ll inf = 0xFFFFFFFFFFFFFFFL; //very large number
priority_queue<int, vector<int>, greater<int> > pq; //for min priority_queue
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

const int MX = 400010;
int MOD = 998244353;
int f[MX];
int rf[MX];

int C(int l,int k, int md) 
{
    if (k<0||k>l){
        return 0;
    }
    return f[l]*rf[k]%md*rf[l-k]%md;
}

void precfac() {
    f[0]=1;
    for (int i=1;i<MX;i++){
        f[i]=f[i-1]*i%MOD;
    }
    rf[MX-1]=powmod(f[MX-1],MOD-2, MOD);
    for (int i=MX-2;i>=0;i--){
        rf[i]=rf[i+1]*(i+1)%MOD;
    }
}
// int MOD = ;
class SegmentTree {
private:
	int n; vii st; vi lz; vi a;
	void merge(int node) {
		st[node].ss=(st[2*node].ss+st[2*node+1].ss)%MOD;
	}
	void build(int node, int lo, int hi) {
		if(lo==hi) {
			st[node]={lo,a[lo]};
			return;
		}
		build(2*node,lo,(lo+hi)/2);
		build(2*node+1,(lo+hi)/2+1,hi);
		merge(node);
	}
	void propagate(int node, int l, int r) {
		if(l!=r) {
			lz[2*node] += lz[node];
			lz[2*node+1] += lz[node];
			lz[2*node] %= MOD;
			lz[2*node+1] %= MOD;
		}
		st[node].ss += (((r-l+1)%MOD)*((lz[node])%MOD))%MOD;
		st[node].ss %= MOD;
		lz[node]=0;
	}
	void update(int node, int l, int r, int lo, int hi, int val) {
		if(lz[node]!=0)
			propagate(node,l,r);
		if(hi < l || lo > r)
			return;
		if(hi >= r && lo <= l) {
			lz[node]+=val;
			lz[node] %= MOD;
			propagate(node,l,r);
			return;
		}
		update(2*node,l,(l+r)/2,lo,hi,val);
		update(2*node+1,(l+r)/2+1,r,lo,hi,val);
		merge(node);
	}
	ii rmq(int node, int l, int r, int lo, int hi) {
		// cout<<l<<" "<<r<<" "<<lo<<" "<<hi<<endl;
		if(lz[node]!=0)
			propagate(node,l,r);
		if(hi < l || lo > r)
			return {-1, 0};
		if(hi >= r && lo <= l)
			return st[node];
		ii d1 = rmq(2*node, l, (l+r)/2, lo, hi);
		ii d2 = rmq(2*node+1, (l+r)/2+1, r, lo, hi);
		return {-1, (d1.ss+d2.ss)%MOD};
	}
public:
	SegmentTree(vi& __a) {
		n = __a.size();
		a=__a;
		st.assign(4*n,{0,0});
		lz.assign(4*n,0);
		build(1,0,n-1);
	}
	void Update(int l, int r, int val) {return update(1,0,n-1,l,r,val);}
	ii RMQ(int l, int r) {return rmq(1,0,n-1,l,r);}
};

signed main(void)
{
	IOS;
	// precfac();
	int n,k; cin>>n>>k;
	vii seg(k);
	for(int i =0 ; i < k; i++)
		cin>>seg[i].ff>>seg[i].ss;
	sort(all(seg));
	vi tmp(n+1,0);
	tmp[1]=1;
	SegmentTree st(tmp);
	for(int i = 1; i<n; i++) {
		for(int j = 0; j < k; j++) {
			int lo = i+seg[j].ff;
			if(lo > n)
				continue;
			int hi = min(n,i+seg[j].ss);
			int old = st.RMQ(i,i).ss;
			// cout<<i<<" "<<lo<<" "<<hi<<" "<<old<<endl;
			st.Update(lo,hi,old);
		}
	}
	cout<<st.RMQ(n,n).ss<<endl;
	return 0;
}

Measured memory_bytes: 25104