import sys
from itertools import permutations
from heapq import heappop,heappush
from collections import deque
import random
import bisect

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    return (g1[n] * g2[r] % mod) * g2[n-r] % mod


mod = 998244353
N = 2*10**5
g1 = [1]*(N+1)
g2 = [1]*(N+1)
inverse = [1]*(N+1)

for i in range( 2, N + 1 ):
    g1[i]=( ( g1[i-1] * i ) % mod )
    inverse[i]=( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2[i]=( (g2[i-1] * inverse[i]) % mod )
inverse[0]=0

N,K = mi()

edge = [set() for v in range(N)]
for _ in range(N):
    u,v = mi()
    edge[u-1].add(v-1)
    edge[v-1].add(u-1)

deq = deque([v for v in range(N) if len(edge[v]) == 1])
rest = N
while deq:
    v = deq.popleft()
    pv = edge[v].pop()
    edge[pv].remove(v)
    rest -= 1
    if len(edge[pv]) == 1:
        deq.append(pv)

dp = [0] * (rest+1)
dp[1] = K
dp[2] = K * (K-1)
for n in range(3,rest+1):
    dp[n] = K * pow(K-1,n-1,mod) - dp[n-1]
    dp[n] %= mod

res = dp[rest] * pow(K-1,N-rest,mod) % mod

print(res)
#print(dp)