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

namespace Tasks
{
    public class D
    {
        static void Main(string[] args)
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);
            Solve();
            Console.Out.Flush();
        }

        public static void Solve()
        {
            var (N, K) = Scanner.Scan<int, int>();
            const int p = 998244353;
            var list = new List<int>();
            for (var i = 0; i < K; i++)
            {
                var (l, r) = Scanner.Scan<int, int>();
                list.AddRange(Enumerable.Range(l, r - l + 1));
            }
            list = list.OrderByDescending(x => x).ToList();
            var dp = new long[N + 1];
            dp[0] = 1;
            dp[1] = 1;
            var skip = 0;
            for (var i = 1; i <= N; i++)
            {
                for (var j = skip; j < list.Count; j++)
                {
                    var d = list[j];
                    if (i + d > N)
                    {
                        skip++;
                        continue;
                    }
                    dp[i + d] += dp[i];
                    dp[i + d] %= p;
                }
            }

            Console.WriteLine(dp[N]);
        }

        public static class Scanner
        {
            private static Queue<string> queue = new Queue<string>();
            public static T Next<T>()
            {
                if (!queue.Any()) foreach (var item in Console.ReadLine().Trim().Split(" ")) queue.Enqueue(item);
                return (T)Convert.ChangeType(queue.Dequeue(), typeof(T));
            }
            public static T Scan<T>() => Next<T>();
            public static (T1, T2) Scan<T1, T2>() => (Next<T1>(), Next<T2>());
            public static (T1, T2, T3) Scan<T1, T2, T3>() => (Next<T1>(), Next<T2>(), Next<T3>());
            public static (T1, T2, T3, T4) Scan<T1, T2, T3, T4>() => (Next<T1>(), Next<T2>(), Next<T3>(), Next<T4>());
            public static (T1, T2, T3, T4, T5) Scan<T1, T2, T3, T4, T5>() => (Next<T1>(), Next<T2>(), Next<T3>(), Next<T4>(), Next<T5>());
            public static IEnumerable<T> ScanEnumerable<T>() => Console.ReadLine().Trim().Split(" ").Select(x => (T)Convert.ChangeType(x, typeof(T)));
        }
    }
}
