MOD = 998244353

N, K = map(int, input().split())
event = []
for i in range(N):
    l, r = map(int, input().split())
    event.append((l, 1))
    event.append((r, 0))
event.sort()


cnt = 0
ans = 1

for i in range(2 * N):
    x, t = event[i]
    if t == 1:
        if cnt == K:
            ans = 0
        else:
            ans *= K - cnt
        cnt += 1
    else:
        cnt -= 1


print((pow(K, N, MOD) - ans) % MOD)