import sys from collections import deque sys.setrecursionlimit(1 << 25) n = int(sys.stdin.readline()) tree = [[] for _ in range(n+1)] for _ in range(n-1): x, y = map(int, sys.stdin.readline().split()) tree[x].append(y) tree[y].append(x) parent = [0] * (n + 1) children = [[] for _ in range(n + 1)] visited = [False] * (n + 1) q = deque([1]) visited[1] = True parent[1] = 0 # root has no parent while q: u = q.popleft() for v in tree[u]: if not visited[v] and v != parent[u]: parent[v] = u children[u].append(v) visited[v] = True q.append(v) parent_uf = list(range(n + 1)) used = [0] * (n + 1) def find(u): while True: if u == 0: return None # root's parent is considered invalid if used[u] < 2: return u if parent_uf[u] == u: return None original_parent = parent_uf[u] parent_uf[u] = find(parent_uf[u]) if parent_uf[u] is None: return None u = parent_uf[u] post_order = [] stack = [(1, False)] visited_p = [False] * (n + 1) while stack: node, processed = stack.pop() if processed: post_order.append(node) continue if visited_p[node]: continue visited_p[node] = True stack.append((node, True)) for child in reversed(children[node]): if not visited_p[child]: stack.append((child, False)) size = [0] * (n + 1) for u in post_order: child_sizes = [] for v in children[u]: child_sizes.append(size[v]) child_sizes.sort(reverse=True) sum_children = sum(child_sizes[:2]) if len(child_sizes) >= 2 else (sum(child_sizes) if len(child_sizes) == 1 else 0) current = 1 + sum_children remaining = child_sizes[2:] if len(child_sizes) > 2 else [] for vsize in remaining: w = find(parent[u]) if w is not None: used[w] += 1 current += vsize if used[w] >= 2: parent_uf[w] = parent[w] if parent[w] != 0 else w # Update parent_uf for next find size[u] = current print(size[1])