import sys
def input():
  return sys.stdin.readline()[:-1]
mod=998244353
N,K=map(int,input().split())
C=[list(map(int,input().split())) for _ in range(N)]
ans=1
tmp=[]
for i in range(N):
  tmp.append((C[i][0]*(10**6),0))
  tmp.append((C[i][1]*(10**6)-1,1))
tmp.sort()
tmp2=K
for i in range(2*N):
  if tmp[i][1]==0:
    ans*=tmp2
    ans%=mod
    if tmp2==0: break
    tmp2-=1
  else: tmp2+=1
print((pow(K,N,mod)-ans)%mod)