using static System.Math;
using static System.Console;
using System.Collections.Generic;
using System.Linq;
using System;

class Program
{
    #region Reader
    static string ReadStr => Console.ReadLine();
    static string[] ReadStrs => Console.ReadLine().Split(' ');
    static int ReadInt => Convert.ToInt32(Console.ReadLine().Trim());
    static int[] ReadInts => Console.ReadLine().Trim().Split(' ').Select(s => Convert.ToInt32(s)).ToArray();
    static long ReadLong => Convert.ToInt64(Console.ReadLine().Trim());
    static long[] ReadLongs => Console.ReadLine().Trim().Split(' ').Select(s => Convert.ToInt64(s)).ToArray();
    #endregion
    #region Method
    const int mod = 1000000007;
    public static int Mod(int a, int mod) { return a % mod >= 0 ? a % mod : a % mod + mod; }
    public static long Mod(long a, long mod = mod) { return a % mod >= 0 ? a % mod : a % mod + mod; }
    #endregion





    /// <summary>
    /// 最大公約数
    /// </summary>
    /// <param name="a"></param>
    /// <param name="b"></param>
    /// <returns></returns>
    public static long Gcd(long a, long b)
    {
        if (a < b)
            // 引数を入替えて自分を呼び出す
            return Gcd(b, a);
        while (b != 0)
        {
            var remainder = a % b;
            a = b;
            b = remainder;
        }
        return a;
    }



    public static Dictionary<int, int> PrimeFactors(int n)
    {
        int i = 2;
        int tmp = n;
        Dictionary<int, int> d = new Dictionary<int, int>();

        while (i * i <= n) //※1
        {
            if (tmp % i == 0)
            {
                tmp /= i;
                if (d.ContainsKey(i)) d[i]++;
                else d.Add(i, 1);
            }
            else
            {
                i++;
            }
        }
        if (tmp != 1)
        {
            if (d.ContainsKey(tmp)) d[tmp]++;
            else d.Add(tmp, 1);
        }
        return d;
    }


    #region Mod
    public static long GetInv(long a, long mod = 1000000007)
    {
        return PowerMod(a, mod - 2, mod);
    }
    public static long Combination(long a, long b, long mod = 1000000007)
    {
        if (b < 0 || b > a) return 0;
        if (b > a / 2) b = a - b;
        long numerator = Factorial(a, mod);
        long denominator = (Factorial(b, mod) * Factorial(a - b, mod)) % mod;

        return (numerator * GetInv(denominator, mod)) % mod;
    }
    public static long Factorial(long n, long mod = 1000000007)
    {
        if (n == 0) return 1;
        if (n == 1) return 1;
        long ans = n;
        for (int i = 2; i < n; i++)
        {
            ans = (ans * i) % mod;
        }

        return ans;
    }
    private static long PowerMod(long a, long n, long mod = 1000000007)
    {
        if (n == 0) return 1;
        if (n == 1) return a;

        long p = PowerMod(a, n / 2, mod);
        if (n % 2 == 1) return ((p * p) % mod * a) % mod;
        else return (p * p) % mod;
    }
    #endregion


    static List<long> Divisor(long N)
    {
        List<long> ans = new List<long>();
        int max = (int)Math.Sqrt(N);
        for (int i = 1; i < max; i++)
        {
            if (N % i == 0)
            {
                ans.Add(i);
                ans.Add(N / i);
            }
        }

        if (N % max == 0)
        {
            if (N / max == max) ans.Add(max);
            else
            {
                ans.Add(max);
                ans.Add(N / max);
            }
        }
        return ans;
    }

    //998244353


    static void Main()
    {
        int[] NK = ReadInts;
        int N = NK[0];
        int K = NK[1];

        long[] spots = new long[N];
        spots[0] = 1;

        List<int> leep = new List<int>();

        for (int i = 0; i < K; i++)
        {
            var s = ReadInts;

            for (int j = s[0]; j <= s[1]; j++)
            {
                leep.Add(j);
            }
        }

        for (int i = 0; i < N; i++)
        {
            for (int l = 0; l < leep.Count; l++)
            {
                if (i + leep[l] < N)
                {
                    spots[i + leep[l]] += spots[i];
                    spots[i + leep[l]] %= 998244353;
                }
            }
        }

        WriteLine(spots[N-1]);
    }
}

