from collections import defaultdict, deque
from typing import List


def build_graph(edges):
    graph = defaultdict(list)
    for edge in edges:
        u, v = edge
        graph[u].append(v)
        graph[v].append(u)
    return graph


def bfs(graph, start):
    visited = set()
    queue = deque([(start, 0)])
    map_level = defaultdict(int)
    map_level[0] += 1
    while queue:
        node, level = queue.popleft()
        print(node, level)
        visited.add(node)
        map_level[level] += 1
        for neighbor in graph[node]:
            if neighbor not in visited:
                queue.append((neighbor, level + 1))
    return map_level


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

graph = build_graph(edges)
map_level = bfs(graph, 1)
print(map_level[target_level - 1])