import sys
input = sys.stdin.readline

N, K = map(int, input().split())
G = [[] for i in range(N)]
deg = [0] * N
for i in range(N):
    u, v = map(int, input().split())
    u, v = u - 1, v - 1
    G[u].append(v)
    G[v].append(u)
    deg[u] += 1
    deg[v] += 1
        
Q = []
for i in range(N):
    if deg[i] == 1:
        Q.append(i)
        
loop = N
while Q:
    u = Q.pop()
    loop -= 1
    for v in G[u]:
        deg[v] -= 1
        if deg[v] == 1:
            Q.append(v)
        
pre0, pre1 = K, 0
mod = 998244353
for _ in range(loop - 2):
    dp0 = pre1
    dp1 = pre0 * (K - 1) + pre1 * (K - 2)
    pre0 = dp0 % mod
    pre1 = dp1 % mod    

ans = pre0 * pow(K - 1, N - loop + 1, mod) + pre1 * (K - 2) * pow(K - 1, N - loop, mod)
print(ans%mod)