import sys
from collections import deque, Counter
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353
class Combinatorics():
    def __init__(self, mod, maxi):
        self.mod = mod
        self.maxi = maxi
        self.facs = [1] * (maxi + 1)
        self.factinvs = [1] * (maxi + 1)
        self.invs = [1] * (maxi + 1)
        for i in range(2, self.maxi + 1):
            self.facs[i] = ((self.facs[i-1] * i) % self.mod)
            self.invs[i] = (-self.invs[self.mod % i] * (self.mod // i)) % self.mod
            self.factinvs[i] = (self.factinvs[i-1] * self.invs[i]) % self.mod
            
    def choose(self, n, k) -> int:
        if k < 0 or k > n: return 0
        if k == 0 or k == n: return 1
        k = min(k, n - k)
        return (((self.facs[n] * self.factinvs[k]) % self.mod) * self.factinvs[n-k]) % self.mod
    
    def perm(self, n, k) -> int:
        return (self.choose(n, k) * self.facs[k]) % self.mod

    def homop(self, n, k) -> int:
        if n == k == 0:
            return 1
        return self.choose(n + k - 1, k)


n, k = mi()
LR = [li() for _ in range(n)]

s = [[] for _ in range(2 * 10 ** 5 + 1)]
t = [[] for _ in range(2 * 10 ** 5 + 1)]

for i, v in enumerate(LR):
    l, r = v
    s[l].append(i)
    t[r].append(i)
S = 0
C = Combinatorics(mod, 3 * 10 ** 5)
ans = 1
for i in range(1, 2 * 10 ** 5 + 1):
    S -= len(t[i])
    for x in range(len(s[i])):
        ans *= (k - S - x)
        ans %= mod
        ans *= C.invs[x + 1]
        ans %= mod
    S += len(s[i])
ans = pow(k, n, mod) - ans
ans %= mod
print(ans)