MOD = 998244353i64

n, k = read_line.split.map(&.to_i)
ord = Array.new(n, 0)
g = Array.new(n) { [] of Int32 }
n.times do
  u, v = read_line.split.map { |v| v.to_i - 1 }
  ord[u] += 1
  ord[v] += 1
  g[u] << v
  g[v] << u
end
q = n.times.select { |i| ord[i] == 1 }.to_a
qi = 0
ans = 1i64
while qi < q.size
  cur = q[qi]
  g[cur].each do |a|
    ord[a] -= 1
    if ord[a] == 1
      q << a
    end
  end
  qi += 1
  ans *= (k - 1)
  ans %= MOD
end
n -= qi
dp = Array.new(n) { Array.new(2, 0i64) }
dp[0][0] = k
1.upto(n - 1) do |i|
  dp[i][0] = dp[i - 1][1]
  dp[i][1] = (dp[i - 1][0] * (k - 1) + dp[i - 1][1] * (k - 2)) % MOD
end
puts ans * dp[-1][1] % MOD