using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k) = (c[0], c[1]);
        var map = NArr(n);
        var mod = 998_244_353;
        var list = new List<Pair>();
        for (var i = 0; i < n; ++i)
        {
            list.Add(new Pair(1, map[i][0]));
            list.Add(new Pair(0, map[i][1]));
        }
        list.Sort();
        var tmp = k;
        var ans = 1L;
        foreach (var li in list)
        {
            if (li.Kind == 1)
            {
                ans = ans * tmp % mod;
                --tmp;
            }
            else ++tmp;
        }
        WriteLine((Exp(k, n, mod) + mod - ans) % mod);
    }
    class Pair : IComparable<Pair>
    {
        public int Kind;
        public int Time;
        public Pair(int pos, int val)
        {
            Kind = pos; Time = val;
        }
        public int CompareTo(Pair b)
        {
            var d = Time.CompareTo(b.Time);
            if (d != 0) return d;
            return Kind.CompareTo(b.Kind);
        }
    }
    static long Exp(long n, long k, int mod)
    {
        if (k == 0) return 1;
        if (k == 1) return n % mod;
        var half = Exp(n, k / 2, mod);
        var result = (half * half) % mod;
        return ((k % 2) == 0) ? result : ((result * n) % mod);
    }
}