N,K = map(int,input().split())
P = 998244353
G = [[] for _ in range(N)]
Gnum = [0] * N
for _ in range(N):
    u,v = map(int,input().split())
    u -= 1
    v -= 1
    G[u].append(v)
    G[v].append(u)
    Gnum[u] += 1
    Gnum[v] += 1

t = 0
stack = []
for i in range(N):
    if Gnum[i] == 1:
        stack.append((i,-1))
        Gnum[i] = 0
        t += 1
while stack:
    now,parent = stack.pop()
    for v in G[now]:
        Gnum[v] -= 1
        if Gnum[v] == 1:
            stack.append((v,now))
            t += 1
C = N - t
dp = [[0] * 2 for _ in range(C)]
dp[0][0] = 1
for i in range(1,C):
    dp[i][0] += dp[i-1][1]
    dp[i][1] += dp[i-1][0] * (K - 1) + dp[i-1][1] * (K - 2)
    dp[i][1] %= P
ans = dp[-1][1] * K % P
ans *= pow(K -1,t,P)
print(ans % P)