#!/usr/bin/env python3
from bisect import bisect_left, bisect_right
from collections import deque
from itertools import permutations
from sys import setrecursionlimit


dpos4 = ((1, 0), (0, 1), (-1, 0), (0, -1))
dpos8 = ((0, -1), (1, -1), (1, 0), (1, 1), (0, 1), (-1, 1), (-1, 0), (-1, -1))
mod1 = 10**9 + 7
mod2 = 998244353
inf = 1 << 60


def main():
    N = int(input())
    edges = [[] for _ in range(N)]
    for _ in range(N - 1):
        u, v = map(int, input().split())
        u -= 1
        v -= 1
        edges[u].append(v)
        edges[v].append(u)

    dp1 = [True] * N
    dp2 = [True] * N

    setrecursionlimit(10**6)

    def dfs1(fr, prev=-1):
        val = False
        for to in edges[fr]:
            if to == prev:
                continue
            dfs1(to, fr)
            val |= dp1[to]
        dp1[fr] = not val

    def dfs2(fr, prev=-1):
        val = False
        for to in edges[fr]:
            val |= dp1[to]
        dp2[fr] = not val
        L = len(edges[fr])
        lval = [False] * (L + 1)
        rval = [False] * (L + 1)
        for i in range(L):
            to = edges[fr][i]
            lval[i + 1] = lval[i] or dp1[to]
            j = L - 1 - i
            to = edges[fr][j]
            rval[j] = rval[j + 1] or dp1[to]
        for i in range(L):
            to = edges[fr][i]
            if to == prev:
                continue
            dp1[fr] = not (lval[i] or rval[i + 1])
            dfs2(to, fr)


    dfs1(0)
    dfs2(0)
    print(sum(dp2))
    print(*(i + 1 for i in range(N) if dp2[i]))


if __name__ == "__main__":
    main()