n,k = map(int,input().split())
lr = []
for _ in range(n):
    l,r = map(int,input().split())
    lr.append((l,1)); lr.append((r,0))
mod = 998244353; c = 0; x = 1
for _,f in sorted(lr):
    if f: x = x*max(k-c,0)%mod; c += 1
    else: c -= 1
print((pow(k,n,mod)-x)%mod)