import collections
N,K = map(int, input().split())
LR = [list(map(int, input().split())) for _ in range(N)]
D = collections.defaultdict(int)
for l,r in LR:
    D[l*2]+=1
    D[r*2-1]-=1
D = sorted(D.items())
mod = 998244353
eat = 0
dp = 1


for k,v in D:
    if k%2==0:
        for _ in range(v):
            dp = (dp*(K-eat))%mod
            eat+=1
    else:
        eat+=v
print((pow(K,N,mod)-dp)%mod)