using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using System.IO.Pipes;

public class HelloWorld
{
    static bool res = false;
    static List<long> avail;
    static long[] memo;
    static public void Main()
    {
        var NK = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();
        var N = NK[0];
        var K = NK[1];

        avail = new List<long>();
        memo = new long[N + 1];
        memo[1] = 1;
        for (int i = 0; i < K; i++)
        {
            var LR = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            for (int j = LR[0]; j <= LR[1]; j++)
            {
                avail.Add(j);
            }
        }


        Console.WriteLine(Check(N).value);
    }

    static Modular Check(long N)
    {
        if (memo[N] > 0) return memo[N];
        var res = new Modular(0);
        foreach (var item in avail)
        {
            if(N - item>= 1)
            {
                res += Check(N - item);
            }
        }

        memo[N] = res.value;
        return memo[N];
    }
}

class Modular
{
    private const int M = 998244353;
    public long value;
    public Modular(long value) { this.value = value; }
    public static implicit operator Modular(long a)
    {
        var m = a % M;
        return new Modular((m < 0) ? m + M : m);
    }
    public static Modular operator +(Modular a, Modular b)
    {
        return (a.value + b.value) % M;
    }
    public static Modular operator -(Modular a, Modular b)
    {
        return a.value - b.value;
    }
    public static Modular operator *(Modular a, Modular b)
    {
        return a.value * b.value;
    }
    public static Modular Pow(Modular a, int n)
    {
        switch (n)
        {
            case 0:
                return 1;
            case 1:
                return a;
            default:
                var p = Pow(a, n / 2);
                return p * p * Pow(a, n % 2);
        }
    }
    public static Modular operator /(Modular a, Modular b)
    {
        return a * Pow(b, M - 2);
    }
    private static readonly List<int> facs = new List<int> { 1 };
    private static Modular Fac(int n)
    {
        for (int i = facs.Count; i <= n; ++i)
        {
            facs.Add((int)(Math.BigMul(facs.Last(), i) % M));
        }
        return facs[n];
    }
    public static Modular Ncr(int n, int r)
    {
        return (n < r) ? 0
             : (n == r) ? 1
                        : Fac(n) / (Fac(r) * Fac(n - r));
    }
    public static explicit operator int(Modular a)
    {
        return (int)a.value;
    }

    public static Modular Lcm(Modular a, Modular b)
    {
        var tmp = Gcdl(a.value, b.value);
        return ((a * b) / new Modular(tmp));
    }
    static Modular Gcd(Modular m, Modular n)
    {
        if (n.value > m.value) return Gcd(n, m);
        if (n.value == 0) return m;
        var r = new Modular(m.value % n.value);
        return Gcd(n, r);
    }

    static long Gcdl(long m, long n)
    {
        if (n > m) return Gcdl(n, m);
        if (n == 0) return m;
        return Gcdl(n, m % n);
    }
}
