from collections import deque

def bfs(x):
    dis = [n]*(n)
    dis[x] = 0
    q = deque([x])
    while q:
        now = q.popleft()
        for nex in e[now]:
            if dis[nex] > dis[now]+1:
                dis[nex] = dis[now]+1
                q.append(nex)
    return dis

def Euler_Tour(x):
    vis = [0]*n
    stack = [~x,x]
    ans = [0]*n
    vis[x] = 1
    count = -1
    while stack:
        now = stack.pop()
        count += 1
        if now >= 0:
            ans[now] = count
            for nex in e[now]:
                if dis[nex] == dis[now]-1 and vis[nex] == 0:
                    vis[nex] = 1
                    stack.append(~nex)
                    stack.append(nex)
            
            for nex in e[now]:
                if vis[nex] == 0:
                    vis[nex] = 1
                    stack.append(~nex)
                    stack.append(nex)
    return ans

n = int(input())
e = [[] for i in range(n)]
for i in range(n-1):
    a,b = map(int,input().split())
    a -= 1
    b -= 1
    e[a].append(b)
    e[b].append(a)

dis = bfs(0)
dis = bfs(dis.index(max(dis)))
print(max(Euler_Tour(dis.index(max(dis)))))