import sys

sys.setrecursionlimit(10 ** 6)
from bisect import *
from collections import *
from heapq import *

int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline()[:-1]
def MI(): return map(int, sys.stdin.readline().split())
def MI1(): return map(int1, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
dij = [(0, 1), (1, 0), (0, -1), (-1, 0)]

class UnionFind:
    def __init__(self, n):
        self.state = [-1] * n
        self.size_table = [1] * n
        # cntはグループ数
        self.cnt = n

    def root(self, u):
        v = self.state[u]
        if v < 0: return u
        self.state[u] = res = self.root(v)
        return res

    def merge(self, u, v):
        ru = self.root(u)
        rv = self.root(v)
        if ru == rv: return
        du = self.state[ru]
        dv = self.state[rv]
        if du > dv: ru, rv = rv, ru
        if du == dv: self.state[ru] -= 1
        self.state[rv] = ru
        self.cnt -= 1
        self.size_table[ru] += self.size_table[rv]
        return

    # グループの要素数
    def size(self, u):
        return self.size_table[self.root(u)]

def main():
    n=II()
    uf=UnionFind(n)
    to=defaultdict(list)
    for _ in range(n-1):
        u,v=MI()
        to[u].append(v)
        to[v].append(u)
        uf.merge(u,v)
    print(uf.size(3))
    if uf.cnt==1:print("Bob")
    elif uf.cnt>2:print("Alice")
    else:
        flag=False
        for u in range(n):
            if len(to[u])>2 or len(to[u])==1:
                print("Alice")
                break
            if len(to[u])==0:
                if flag:
                    print("Alice")
                    break
                else:
                    flag=True
        else:
            print("Bob")

main()