import sys
input = sys.stdin.readline

mod=998244353

N,K=map(int,input().split())
DEG=[0]*(N+5)

E=[[] for i in range(N+1)]

for i in range(N):
    x,y=map(int,input().split())
    E[x].append(y)
    E[y].append(x)
    DEG[x]+=1
    DEG[y]+=1

Q=[]
for i in range(N+1):
    if DEG[i]==1:
        Q.append(i)

#print(DEG)

while Q:
    x=Q.pop()
    DEG[x]-=1
    for to in E[x]:
        DEG[to]-=1
        if DEG[to]==1:
            Q.append(to)

L=0
for i in range(N+5):
    if DEG[i]==2:
        L+=1

DP=[1,0]

for i in range(L-1):
    NDP=[0,0]

    NDP[0]=DP[1]
    NDP[1]=DP[0]*(K-1)+DP[1]*(K-2)

    DP[0]=NDP[0]%mod
    DP[1]=NDP[1]%mod

ANS=K*DP[1]*pow(K-1,N-L,mod)%mod

print(ANS)