N,K = map(int,input().split())
G = [[] for i in range(N)]
d = [0 for i in range(N)]
mod = 998244353
for i in range(N):
  u,v = map(int,input().split())
  G[u-1].append(v-1)
  G[v-1].append(u-1)
  d[u-1] += 1
  d[v-1] += 1

H = []
for u in range(N):
  if d[u] == 1:
    H.append(u)

c = 0
while len(H):
  u = H.pop()
  for v in G[u]:
    d[v] -= 1
    if d[v] == 1:
      H.append(v)
  c += 1

ans = pow(K-1,c,mod)
r = N - c
dp = [[0,0] for i in range(r)]
dp[0][1] = K
for i in range(r-1):
  dp[i+1][0] += (K-2) * sum(dp[i]) + dp[i][1]
  dp[i+1][0] %= mod
  dp[i+1][1] += dp[i][0]
  dp[i+1][1] %= mod

ans *= dp[-1][0]
ans %= mod
print(ans)