import sys

# sys.setrecursionlimit(1000005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 63)
# md = 10**9+7
md = 998244353

def find_loop(to, root=0):
    n = len(to)
    fin = [0]*n
    res = []
    st = [(root, -1, True)]
    while st:
        u, par, first = st.pop()
        if res:
            if u == res[0]: return res
            if first: continue
            res.append(u)
        elif first:
            fin[u] = 1
            st.append((u, par, False))
            for v in to[u]:
                if v == par:
                    continue
                if fin[v]:
                    res.append(v)
                    break
                st.append((v, u, True))
        else:
            fin[u] = 2
    return res

n,k=LI()
to=[[] for _ in range(n)]
for _ in range(n):
    u,v=LI1()
    to[u].append(v)
    to[v].append(u)

loop=find_loop(to,0)

x,y=k,0
for _ in range(len(loop)-1):
    x,y=y,(x*(k-1)%md+y*(k-2)%md)%md

ans=pow(k-1,n-len(loop),md)*y%md
print(ans)