import sys

sys.setrecursionlimit(200005)
# 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 << 62)

md = 10**9+7
# md = 998244353

n = II()
to = [[] for _ in range(n)]
for _ in range(n-1):
    u, v = LI1()
    to[u].append(v)
    to[v].append(u)

def rerooting(root=0):
    uu = []
    stack = [root]
    while stack:
        u = stack.pop()
        uu.append(u)
        vv = []
        # !!!check the format of the "to"!!!
        for v in to[u]:
            if v == par[u]: continue
            vv.append(v)
            par[v] = u
            stack.append(v)
            rdp[v] = dp[u]
        to[u] = vv

    # bottom up
    for u in uu[::-1]:
        p = par[u]
        if p != -1:
            trans_up(u)
            dp[p] = op(dp[p], dp[u])

    # top down
    for u in uu:
        cs = e()
        # !!!check the format of the "to"!!!
        for v in to[u]:
            rdp[v] = op(rdp[v], cs)
            cs = op(cs, dp[v])
        cs = rdp[u]
        for v in to[u][::-1]:
            rdp[v] = op(rdp[v], cs)
            trans_down(v)
            cs = op(cs, dp[v])
        dp[u] = cs

def op(a, b):
    return a & b

# u to parent[u]
def trans_up(u):
    dp[u] ^= 1
    return

# parent[u] to u
def trans_down(u):
    rdp[u] ^= 1
    return

e = lambda: 1
par = [-1]*n

# dp初期化
dp = [e() for _ in range(n)]
rdp = [e() for _ in range(n)]

rerooting()

print(sum(dp))
for u in range(n):
    if dp[u]:print(u+1)