n = int(input())
S = list(map(int, input().split()))
T = list(map(int, input().split()))

ds = [set() for i in range(3)]
dt = [set() for i in range(3)]

for i, s in enumerate(S):
    ds[s].add(i)
for i, t in enumerate(T):
    dt[t].add(i)

A = [[0]*n for _ in range(n)]
for i in ds[2]:
    for j in range(n):
        A[i][j] = 1

for j in dt[2]:
    for i in range(n):
        A[i][j] = 1

for i in ds[1]:
    cnt = 0
    for j in range(n):
        if A[i][j] == 1:
            cnt += 1
    if cnt == 0:
        for j in range(n):
            if j not in dt[0] and j in dt[1]:
                A[i][j] = 1
                dt[1].remove(j)
                break

for j in dt[1]:
    cnt = 0
    for i in range(n):
        if A[i][j] == 1:
            cnt += 1
    if cnt == 0:
        for i in range(n):
            if i not in ds[0] and ds[1]:
                A[i][j] = 1
                ds[1].remove(i)
                break
#print(A)
ans = 0
for i in range(n):
    for j in range(n):
        ans += A[i][j]
print(ans)