import sys
import math

# Auto-generated code below aims at helping you parse
# the standard input according to the problem statement.
network = dict()

n = int(input())  # the number of adjacency relations
for i in range(n):
    # xi: the ID of a person which is adjacent to yi
    # yi: the ID of a person which is adjacent to xi
    xi, yi = [int(j) for j in input().split()]
    if xi not in network.keys():
        network[xi] = [yi]
    else:
        network[xi].append(yi)
    if yi not in network.keys():
        network[yi] = [xi]
    else:
        network[yi].append(xi)

print(network, file = sys.stderr)

# Write an action using print
# To debug: print("Debug messages...", file=sys.stderr)
# The minimal amount of steps required to completely propagate the advertisement

def find_path(start):
    """This function determines the number of steps required to completely propagate a message
    across a network from a starting node position"""

    visited = []
    step = 0
    roots = [start]

    # Until all the nodes in the network have been visited
    while len(visited) != len(network):
        children = []

        # Only count nodes that are not in visited
        roots = list(set(roots) - set(visited))
        visited.extend(roots)

        # Find children for every root node
        for root in roots:
            child = network[root]
            children.extend(child)

        # If one child is not in visited => new link => add step
        if len(list(set(children).intersection(set(visited)))) > 0:
            step += 1

        roots.extend(list(set(children) - set(visited)))

    return step


steps_list = []
# Go through all keys in network to find the minimum amount of steps
for key in network.keys():
    steps = find_path(key)
    steps_list.append(steps)

print(min(steps_list))