n,k = map(int,input().split())
lr = [[v-1 for v in map(int,input().split())] for _ in range(n)]
imos = [0]*(200000); x = 1; mod = 998244353
for l,r in lr: imos[l] += 1; imos[r] -= 1
for i in range(199999): imos[i+1] += imos[i]
for l,_ in lr: x *= max(k-imos[l]+1,0); x %= mod
print((pow(k,n,mod)-x)%mod)