N = int(input())

V = [[] for _ in range(N)]

for _ in range(N-1):
    a, b = map(int, input().split())
    V[a-1].append(b-1)
    V[b-1].append(a-1)
    
def dfs(prev, i, n):
    if len(V[i]) == 1 and V[i][0] == prev:
        return (n, i)
    rtn = (-1, -1)
    for j in V[i]:
        if j != prev:
            rtn = max(rtn, dfs(i, j, n+1))
    return rtn

n, u= dfs(-1, 0, 0)
n, v = dfs(-1, u, 0)

print(2*(N-1)-n)