using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
using System.Threading;
static class Program{
	const int mod=(int)1e9+7;
	const double eps=1e-11;
	static void Main(){
		Sc sc=new Sc();
		var s=sc.Ia;
		var a=new int[s[1]][];
		for(int i = 0;i<s[1];i++) {
			a[i]=sc.Ia;
		}
		Bit2 bit=new Bit2(s[0]+1);
		bit.Ud(1,1,1);
		for(int i = 1;i<s[0];i++) {
			var d=bit.Get(i,i);
			for(int j = 0;j<s[1];j++) {
				if(a[j][0]+i>s[0]){continue;}
				bit.Ud(a[j][0]+i,Min(a[j][1]+i,s[0]),d);
			}
		}
		Console.WriteLine("{0}",bit.Get(s[0],s[0]));
	}
}
public class Bit2{
	const int mod=998244353;
	private int n;
	private Bit bit1,bit2;
	public Bit2(int n){
		this.n=n;
		bit1=new Bit(n);
		bit2=new Bit(n);
	}
	public void Ud(int l,int r,Mint p){
		bit1.Ud(l,(mod-p)*(l-1));
		bit2.Ud(l,p);
		bit1.Ud(r+1,p*r);
		bit2.Ud(r+1,mod-p);
	}
	public Mint Get(int l,int r){return bit2.Get(r)*r+bit1.Get(r)-bit2.Get(l-1)*(l-1)-bit1.Get(l-1);}
	public class Bit{
		private int n;
		private Mint[] bit;
		public Bit(int n){
			this.n=n;
			bit=new Mint[n+1];
		}
		public void Ud(int a,Mint p){a++;while(a<=n){bit[a]+=p;a+=a&-a;}}
		public Mint Get(int n){
			n++;
			Mint a=0;
			while(n>0){a+=bit[n];n-=n&-n;}
			return a;
		}
		public void Clear(){bit=new Mint[n+1];}
	}
}
public struct Mint{
	const int mod=998244353;
	private long d;
	public Mint(long d){this.d=d;}
	public static implicit operator Mint(long d){return new Mint(d%mod);}
	public static explicit operator long(Mint d){return d.d;}
	public override string ToString(){return d.ToString();}
	public static Mint operator+(Mint a,long b){a.d=(a.d+b)%mod;return a;}
	public static Mint operator+(Mint a,Mint b){a.d=(a.d+b.d)%mod;return a;}
	public static Mint operator-(Mint a,long b){a.d=(mod+a.d-b)%mod;return a;}
	public static Mint operator-(Mint a,Mint b){a.d=(mod+a.d-b.d)%mod;return a;}
	public static Mint operator*(Mint a,long b){a.d=(a.d*b)%mod;return a;}
	public static Mint operator*(Mint a,Mint b){a.d=(a.d*b.d)%mod;return a;}
	public static Mint operator/(Mint a,long b){a.d=(a.d*Mi(b))%mod;return a;}
	public static Mint operator/(Mint a,Mint b){a.d=(a.d*Mi(b.d))%mod;return a;}
	private static long Mi(long a){
		a=(a+mod)%mod;
		long b=mod,u=1,v=0;
		while(b>0){
			long t=a/b;
			a-=t*b;(a,b)=(b,a);
			u-=t*v;(u,v)=(v,u);
		}
		u%=mod;
		if(u<0){u+=mod;}
		return u%mod;
	}
}
public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}

Measured memory_bytes: 30712