n,k = map(int,input().split())
e = [[] for i in range(n)]
mod = 998244353

count = [0]*n
for _ in range(n):
    u,v = [int(x)-1 for x in input().split()]
    e[u].append(v)
    e[v].append(u)
    count[u] += 1
    count[v] += 1


vis = [0]*n

q = []
for i in range(n):
    if count[i] == 1:
        q.append(i)


while q:
    now = q.pop()
    vis[now] = 1

    for nex in e[now]:
        count[nex] -= 1
        if count[nex] == 1:
            q.append(nex)



assert sum(vis) < n


size = n - sum(vis)
dp = [k,0]

for _ in range(size-1):

    dp = [dp[1],dp[0]*(k-1)+dp[1]*(k-2)]
    dp[0] %= mod
    dp[1] %= mod

ans = dp[1] * pow(k-1,sum(vis),mod)
ans %= mod

print(ans)