import sys

# sys.setrecursionlimit(1000005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

from heapq import *

n, k = LI()
lr = LLI(n)

hp = []
for i, (l, r) in enumerate(lr):
    heappush(hp, (l, 1, r))

s = 1
cnt = 0
while hp:
    t, come, r = heappop(hp)
    if come:
        s *= k-cnt
        s %= md
        cnt += 1
        heappush(hp, (r, 0, -1))
    else:
        cnt -= 1

# print(s)
ans = pow(k, n, md)-s
print(ans%md)