import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
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)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 1 << 63
# md = 998244353
md = 10**9+7

def dfs(to, root=0):
    n = len(to)
    par = [-1]*n
    go = [True]*n
    stack = [root]
    loop = -1
    while stack:
        u = stack.pop()

        if go[u]:
            go[u] = False
            stack.append(u)
            # toの変数注意
            for v in to[u]:
                if v == par[u]: continue
                if not go[v]:
                    return v, u, par
                stack.append(v)
                par[v] = u

        else:
            # toの変数注意
            for v in to[u]:
                if v == par[u]: continue

n = II()
to = [[] for _ in range(n)]
uvtoi = {}
for i in range(n):
    u, v = LI1()
    to[u].append(v)
    to[v].append(u)
    uvtoi[u, v] = uvtoi[v, u] = i

p, u, par = dfs(to, 0)
uu = [p, u]
while uu[-1] != p:
    v = par[uu[-1]]
    uu.append(v)

ans = []
for u, v in zip(uu, uu[1:]):
    ans.append(uvtoi[u, v]+1)

print(len(ans))
print(*ans)