Tree is a connected graph without cycles. A leaf of a tree is any vertex connected with exactly one other vertex.

You are given a tree with n vertices and a root in the vertex 1. There is an ant in each leaf of the tree. In one second some ants can simultaneously go to the parent vertex from the vertex they were in. No two ants can be in the same vertex simultaneously except for the root of the tree.

Find the minimal time required for all ants to be in the root of the tree. Note that at start the ants are only in the leaves of the tree.

Input

The first line contains integer n (2 ≤ n ≤ 5·105) — the number of vertices in the tree.

Each of the next n - 1 lines contains two integers xi, yi (1 ≤ xi, yi ≤ n) — the ends of the i-th edge. It is guaranteed that you are given the correct undirected tree.

Output

Print the only integer t — the minimal time required for all ants to be in the root of the tree.

Examples

Input

12
1 2
1 3
1 4
2 5
2 6
3 7
3 8
3 9
8 10
8 11
8 12


Output

6


Input

2
2 1


Output

1
#### IMPORTANT LIBRARY ####
 
############################
### DO NOT USE import random --> 250ms to load the library
############################
 
### In case of extra libraries: https://github.com/cheran-senthil/PyRival
 
######################
####### IMPORT #######
######################
 
from functools import cmp_to_key 
from collections import deque, Counter
from heapq import heappush, heappop
from math import log, ceil
 
######################
#### STANDARD I/O ####
######################
 
import sys
import os
from io import BytesIO, IOBase
 
BUFSIZE = 8192
 
class FastIO(IOBase):
    newlines = 0
    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None
 
    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()
 
    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()
 
    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)
 
class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")
 
if sys.version_info[0] < 3:
    sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
else:
    sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)

"""
def print(*args, **kwargs):
    sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
    at_start = True
    for x in args:
        if not at_start:
            file.write(sep)
        file.write(str(x))
        at_start = False
    file.write(kwargs.pop("end", "\n"))
    if kwargs.pop("flush", False):
        file.flush()
"""

def inp():
    return sys.stdin.readline().rstrip("\r\n")  # for fast input
    
def ii():
    return int(inp())
 
def si():
    return str(inp())
 
def li(lag = 0):
    l = list(map(int, inp().split()))
    if lag != 0:
        for i in range(len(l)):
            l[i] += lag
    return l
    
def mi(lag = 0):
    matrix = list()
    for i in range(n):
        matrix.append(li(lag))
    return matrix
 
def lsi(): #string list
    return list(map(str, inp().split()))
 
def print_list(lista, space = " "):
    print(space.join(map(str, lista)))
 
######################
### BISECT METHODS ###
######################
 
def bisect_left(a, x):
    """i tale che a[i] >= x e a[i-1] < x"""
    left = 0
    right = len(a)
    while left < right:
        mid = (left+right)//2
        if a[mid] < x: 
            left = mid+1
        else: 
            right = mid
    return left
 
def bisect_right(a, x):
    """i tale che a[i] > x e a[i-1] <= x"""
    left = 0
    right = len(a)
    while left < right:
        mid = (left+right)//2
        if a[mid] > x: 
            right = mid
        else: 
            left = mid+1
    return left
 
def bisect_elements(a, x):
    """elementi pari a x nell'árray sortato"""
    return bisect_right(a, x) - bisect_left(a, x)
 
######################
### MOD OPERATION ####
######################
 
MOD = 10**9 + 7
maxN = 5
FACT = [0] * maxN
INV_FACT = [0] * maxN
 
def add(x, y):
    return (x+y) % MOD
   
def multiply(x, y):
    return (x*y) % MOD
 
def power(x, y):
    if y == 0:
        return 1
    elif y % 2:
        return multiply(x, power(x, y-1))
    else:
        a = power(x, y//2)
        return multiply(a, a)
 
def inverse(x):
    return power(x, MOD-2)
   
def divide(x, y):
    return multiply(x, inverse(y))
 
def allFactorials():
    FACT[0] = 1
    for i in range(1, maxN):
        FACT[i] = multiply(i, FACT[i-1])
 
def inverseFactorials():
    n = len(INV_FACT)
    INV_FACT[n-1] = inverse(FACT[n-1])
    for i in range(n-2, -1, -1):
        INV_FACT[i] = multiply(INV_FACT[i+1], i+1)
 
def coeffBinom(n, k):
    if n < k:
        return 0
    return multiply(FACT[n], multiply(INV_FACT[k], INV_FACT[n-k]))
 
######################
#### GRAPH ALGOS #####
######################
 
# ZERO BASED GRAPH
def create_graph(n, m, undirected = 1, unweighted = 1):
    graph = [[] for i in range(n)]
    if unweighted:
        for i in range(m):
            [x, y] = li(lag = -1)
            graph[x].append(y)
            if undirected:
                graph[y].append(x)
    else:
        for i in range(m):
            [x, y, w] = li(lag = -1)
            w += 1
            graph[x].append([y,w])
            if undirected:
                graph[y].append([x,w])
    return graph
 
def create_tree(n, unweighted = 1):
    children = [[] for i in range(n)]
    if unweighted:
        for i in range(n-1):
            [x, y] = li(lag = -1)
            children[x].append(y)
            children[y].append(x)
    else:
        for i in range(n-1):
            [x, y, w] = li(lag = -1)
            w += 1
            children[x].append([y, w])
            children[y].append([x, w])
    return children
   
def dist(tree, n, A, B = -1):
    s = [[A, 0]]
    massimo, massimo_nodo = 0, 0
    distanza = -1
    v = [-1] * n
    while s:
        el, dis = s.pop() 
        if dis > massimo:
            massimo = dis
            massimo_nodo = el
        if el == B:
            distanza = dis
        for child in tree[el]:
            if v[child] == -1:
                v[child] = 1
                s.append([child, dis+1])
    return massimo, massimo_nodo, distanza
 
def diameter(tree):
    _, foglia, _ = dist(tree, n, 0)
    diam, _, _ = dist(tree, n, foglia)
    return diam
   
def dfs(graph, n, A):
    v = [-1] * n
    s = [[A, 0]]
    v[A] = 0
    while s:
        el, dis = s.pop()
        for child in graph[el]:
            if v[child] == -1:
                v[child] = dis + 1
                s.append([child, dis + 1])
    return v #visited: -1 if not visited, otherwise v[B] is the distance in terms of edges
 
def bfs(graph, n, A):
    v = [-1] * n
    s = deque()
    s.append([A, 0])
    v[A] = 0
    while s:
        el, dis = s.popleft()
        for child in graph[el]:
            if v[child] == -1:
                v[child] = dis + 1
                s.append([child, dis + 1])
    return v #visited: -1 if not visited, otherwise v[B] is the distance in terms of edges
 
#FROM A GIVEN ROOT, RECOVER THE STRUCTURE
def parents_children_root_unrooted_tree(tree, n, root = 0):
    q = deque()
    visited = [0] * n
    parent = [-1] * n
    children = [[] for i in range(n)]
    q.append(root)
    while q:
        all_done = 1
        visited[q[0]] = 1
        for child in tree[q[0]]:
            if not visited[child]:
                all_done = 0
                q.appendleft(child)
        if all_done:
            for child in tree[q[0]]:   
                if parent[child] == -1:
                    parent[q[0]] = child
                    children[child].append(q[0])
            q.popleft()
    return parent, children
 
# CALCULATING LONGEST PATH FOR ALL THE NODES 
def all_longest_path_passing_from_node(parent, children, n):
    q = deque()
    visited = [len(children[i]) for i in range(n)]
    downwards = [[0,0] for i in range(n)]
    upward = [1] * n
    longest_path = [1] * n
    for i in range(n):
        if not visited[i]:
            q.append(i)
            downwards[i] = [1,0]
    while q:
        node = q.popleft()
        if parent[node] != -1:
            visited[parent[node]] -= 1
            if not visited[parent[node]]:
                q.append(parent[node])
        else:
            root = node
        for child in children[node]:   
            downwards[node] = sorted([downwards[node][0], downwards[node][1], downwards[child][0] + 1], reverse = True)[0:2]
    s = [node]
    while s:
        node = s.pop()
        if parent[node] != -1:
            if downwards[parent[node]][0] == downwards[node][0] + 1:
                upward[node] = 1 + max(upward[parent[node]], downwards[parent[node]][1])
            else:
                upward[node] = 1 + max(upward[parent[node]], downwards[parent[node]][0])
        longest_path[node] = downwards[node][0] + downwards[node][1] + upward[node] - min([downwards[node][0], downwards[node][1], upward[node]]) - 1
        for child in children[node]:
            s.append(child)
    return longest_path
 
### TBD SUCCESSOR GRAPH 7.5
### TBD TREE QUERIES 10.2 da 2 a 4
### TBD ADVANCED TREE 10.3
### TBD GRAPHS AND MATRICES 11.3.3 e 11.4.3 e 11.5.3 (ON GAMES)
 
######################
## END OF LIBRARIES ##
######################


n = ii()
tree = create_tree(n)
parent, children = parents_children_root_unrooted_tree(tree, n, root = 0)

res = 0
for ch in tree[0]:
    prof = list()
    stack = list()
    stack.append([ch,0])
    while stack:
        node, p = stack.pop()
        if not children[node]:
            prof.append(p)
        for child in children[node]:
            stack.append([child,p+1])
    prof.sort()
    tv = prof[0]
    for i in range(1,len(prof)):
        tv = max(prof[i],tv+1)
    res = max(res,tv)
    
print(res+1)

