import sys

def input():
    return sys.stdin.readline().rstrip()
sys.setrecursionlimit(1000000)


from collections import deque

def slv():
    n = int(input())
    g = [[] for i in range(n)]
    for i in range(n - 1):
        u,v = map(int,input().split())
        u -= 1
        v -= 1
        g[u].append(v)
        g[v].append(u)
    INF = 1 << 32

    visited = [INF]*(n)
    visited[0] = 0

    stack = deque([0])
    while stack:
        p = stack.popleft()
        for q in g[p]:
            if visited[q] == INF:
                visited[q] = visited[p] + 1
                stack.append(q)
    
    S = 0
    distS = visited[S]
    for i in range(n):
        if visited[i] > distS:
            S = i 
            distS = visited[i]
    
    visited = [INF]*(n)
    visited[S] = 0

    stack = deque([S])
    while stack:
        p = stack.popleft()
        for q in g[p]:
            if visited[q] == INF:
                visited[q] = visited[p] + 1
                stack.append(q) 
    print(2 *n - 2 - max(visited))
    return 

def main():
    t = 1
    for i in range(t):
        slv()
    return 


if __name__ == "__main__":
    main()