n = int(input())
degree = [0] * (n + 1)

# Read red edges
for _ in range(n-1):
    a, b = map(int, input().split())
    degree[a] += 1
    degree[b] += 1

# Read black edges (not used in calculation)
for _ in range(n-1):
    c, d = map(int, input().split())

# Count leaves in red tree
m = sum(1 for i in range(1, n+1) if degree[i] == 1)
print(n + m - 3)