using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Numerics;
using System.Threading;
using System.Runtime.CompilerServices;
using System.Diagnostics;
using static System.Math;
using static System.Array;
using static AtCoder.Cout;
using static AtCoder.Tool;
using static AtCoder.ModInt;
namespace AtCoder
{
    class AC
    {
        //const int MOD = 1000000007;
        const int MOD = 998244353;
        const int INF = int.MaxValue / 2;
        const long SINF = long.MaxValue / 3;
        static readonly int[] dI = { 0, 1, 0, -1, 1, -1, -1, 1 };
        static readonly int[] dJ = { 1, 0, -1, 0, 1, 1, -1, -1 };
        static void Main(string[] args)
        {
            //var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; Console.SetOut(sw);

            /*var th = new Thread(Run, 1 << 26);
            th.Start();
            th.Join();*/

            Run();
            Console.Out.Flush();
        }
        static void Run()
        {
            int Testcase = 1;
            //Testcase = Cin.Int;
            for (var _ = 0; _ < Testcase; _++) Solve();
        }
        static void Solve()
        {
            
            
            Cin.Scanf(out int N, out int K);
            int M = Cin.Int;
            var R = new int[K + 1];//終点が i の区間のうち L の最大値（存在しないなら-1）
            Fill(R, -1);
            for(var i = 0; i < M; i++)
            {
                Cin.Scanf(out int ll, out int rr);
                R[rr] = Max(R[rr], ll);
            }
            for(var i = K; i >= 1; i--)
            {
                var ok = true;
                for(var j = i - 1; j >= 1; j--)
                {
                    ok &= R[j] < R[i];
                }
                if (!ok) R[i] = -1;
            }
            var dpj = new long[K + 1][][];
            var dpjk = new long[K + 1][][];
            for(var i = 0; i <= K; i++)
            {
                dpj[i] = new long[K + 1][];
                dpjk[i] = new long[K + 1][];
                for(var j = 0; j <= K; j++)
                {
                    dpj[i][j] = new long[2];
                    dpjk[i][j] = new long[2];
                }
            }
            dpj[0][0][0] = 1;
            dpjk[0][0][0] = 1;
            for(var j = 1; j <= K; j++)
            {
                for(var k = 0; k <= K; k++)
                {
                    long[] nx = { 0, 0 };
                    if (R[j] != -1 && k > 0)
                    {
                        int L = R[j];
                        for(var l = 0; l < 2; l++)
                        {
                            nx[l] += dpjk[j - 1][k - 1][l ^ 1];
                            if (k - (j - L) - 1 >= 0) nx[l] -= dpjk[L - 1][k - (j - L) - 1][l ^ 1];

                            if (k - (j - L) - 1 >= 0) nx[l] += dpj[L - 1][k - (j - L) - 1][l ^ 1];
                            nx[l] %= MOD;
                            if (nx[l] < 0) nx[l] += MOD;
                        }
                    }
                    for(var l = 0; l < 2; l++)
                    {
                        dpj[j][k][l] = (dpj[j - 1][k][l] + nx[l]) % MOD;
                        dpjk[j][k][l] = (nx[l]);
                        if (j > 0 && k > 0) dpjk[j][k][l] += dpjk[j - 1][k - 1][l];
                        dpjk[j][k][l] %= MOD;
                    }
                }
            }

            ModInt ans = 0;
            for(var k = 0; k <= K; k++)
            {
                ans += (dpj[K][k][0] - dpj[K][k][1]) * Modpow(K - k, N);
            }
            OutL(ans);
        }
    }
    struct ModInt
    {
        public long value;
        //const int MOD = 1000000007;
        const int MOD = 998244353;
        public ModInt(long value) { this.value = value; }
        public override string ToString() => value.ToString();
        public static implicit operator ModInt(long a)
        {
            var ret = a % MOD;
            return new ModInt(ret < 0 ? (ret + MOD) : ret);
        }
        public static ModInt operator +(ModInt a, ModInt b) => (a.value + b.value);
        public static ModInt operator -(ModInt a, ModInt b) => (a.value - b.value);
        public static ModInt operator *(ModInt a, ModInt b) => (a.value * b.value);
        public static ModInt operator /(ModInt a, ModInt b) => a * Modpow(b, MOD - 2);

        public static ModInt operator <<(ModInt a, int n) => (a.value << n);
        public static ModInt operator >>(ModInt a, int n) => (a.value >> n);
        public static ModInt operator ++(ModInt a) => a.value + 1;
        public static ModInt operator --(ModInt a) => a.value - 1;
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static ModInt Modpow(ModInt a, long n)
        {
            if (n == 0) return 1;
            if (n < 0) return Modpow(Modpow(a, -n), MOD - 2);
            var k = a;
            ModInt ret = 1;
            while (n > 0)
            {
                if ((n & 1) != 0) ret *= k;
                k *= k;
                n >>= 1;
            }
            return ret;
        }
        private static readonly List<long> Factorials = new List<long>() { 1 };
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static ModInt Fac(int n)
        {
            if (n < 0) return 0;
            for (var i = Factorials.Count(); i <= n; i++)
            {
                Factorials.Add((Factorials[i - 1] * i) % MOD);
            }
            return Factorials[n];
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static ModInt nCr(int n, int r)
        {
            if (n < 0 || r < 0) return 0;
            return n < r ? 0 : Fac(n) / (Fac(r) * Fac(n - r));
        }
        public static explicit operator int(ModInt a) => (int)a.value;
    }
    static class Cin
    {
        public static string[] ReadSplit => Console.ReadLine().Split();
        public static int[] ReadSplitInt => ConvertAll(ReadSplit, int.Parse);
        public static long[] ReadSplitLong => ConvertAll(ReadSplit, long.Parse);
        public static double[] ReadSplit_Double => ConvertAll(ReadSplit, double.Parse);
        public static string Str => Console.ReadLine();
        public static int Int => int.Parse(Console.ReadLine());
        public static long Long => long.Parse(Console.ReadLine());
        public static double Double => double.Parse(Console.ReadLine());
        public static T Conv<T>(string input)
        {
            if (typeof(T).Equals(typeof(ModInt)))
            {
                return (T)(dynamic)(long.Parse(input));
            }
            return (T)Convert.ChangeType(input, typeof(T));
        }
        public static void Scanf<T>(out T a) => a = Conv<T>(Console.ReadLine());
        public static void Scanf<T, U>(out T a, out U b)
        { var q = ReadSplit; a = Conv<T>(q[0]); b = Conv<U>(q[1]); }
        public static void Scanf<T, U, V>(out T a, out U b, out V c)
        { var q = ReadSplit; a = Conv<T>(q[0]); b = Conv<U>(q[1]); c = Conv<V>(q[2]); }
        public static void Scanf<T, U, V, W>(out T a, out U b, out V c, out W d)
        { var q = ReadSplit; a = Conv<T>(q[0]); b = Conv<U>(q[1]); c = Conv<V>(q[2]); d = Conv<W>(q[3]); }
        public static void Scanf<T, U, V, W, X>(out T a, out U b, out V c, out W d, out X e)
        { var q = ReadSplit; a = Conv<T>(q[0]); b = Conv<U>(q[1]); c = Conv<V>(q[2]); d = Conv<W>(q[3]); e = Conv<X>(q[4]); }
    }
    static class Cout
    {
        public static void OutL(object s) => Console.WriteLine(s);
        public static void Out_Sep<T>(IEnumerable<T> s) => Console.WriteLine(string.Join(" ", s));
        public static void Out_Sep<T>(IEnumerable<T> s, string sep) => Console.WriteLine(string.Join($"{sep}", s));
        public static void Out_Sep(params object[] s) => Console.WriteLine(string.Join(" ", s));
        public static void Out_One(object s) => Console.Write($"{s} ");
        public static void Out_One(object s, string sep) => Console.Write($"{s}{sep}");
        public static void Endl() => Console.WriteLine();
    }
    public static class Tool
    {
        static public void Initialize<T>(ref T[] array, T initialvalue)
        {
            array = ConvertAll(array, x => initialvalue);
        }
        static public void Swap<T>(ref T a, ref T b)
        {
            T keep = a;
            a = b;
            b = keep;
        }
        static public void Display<T>(T[,] array2d, int n, int m)
        {
            for (var i = 0; i < n; i++)
            {
                for (var j = 0; j < m; j++)
                {
                    Console.Write($"{array2d[i, j]} ");
                }
                Console.WriteLine();
            }
        }
        static public long Gcd(long a, long b)
        {
            if (a == 0 || b == 0) return Max(a, b);
            return a % b == 0 ? b : Gcd(b, a % b);
        }
        static public bool Bit(long x, int dig) => ((1L << dig) & x) != 0;
        static public int Sig(long a) => a == 0 ? 0 : (int)(a / Abs(a));
    }
}