import java.io.BufferedReader import java.io.InputStream import java.io.InputStreamReader import java.lang.AssertionError import java.util.* import kotlin.math.abs import kotlin.math.max import kotlin.math.min val MOD = 1_000_000_007 class Solver(stream: InputStream, private val out: java.io.PrintWriter) { private val reader = BufferedReader(InputStreamReader(stream), 32768) private val N = ni() private val S = na(N) private val T = na(N) private val grid = Array(N){IntArray(N) } fun solve() { for (i in 0 until N) { if (S[i] == 2) { for (j in 0 until N) { grid[i][j] = 1 } } } for (j in 0 until N) { if (T[j] == 2) { for (i in 0 until N) { grid[i][j] = 1 } } } var row = 0 var col = 0 for (i in 0 until N) { if (S[i] == 1 && !grid[i].contains(1)) { row++ } } for (j in 0 until N) { if (T[j] != 1) continue var cnt = 0 for (i in 0 until N) { if (grid[i][j] == 1) cnt++ } if (cnt == 0) col++ } var ans = grid.map{it.count{it == 1}}.sum() ans += max(row, col) out.println(ans) } private val isDebug = try { // なんか本番でエラーでる System.getenv("MY_DEBUG") != null } catch (t: Throwable) { false } private var tokenizer: StringTokenizer? = null private fun next(): String { while (tokenizer == null || !tokenizer!!.hasMoreTokens()) { tokenizer = StringTokenizer(reader.readLine()) } return tokenizer!!.nextToken() } private fun ni() = next().toInt() private fun nl() = next().toLong() private fun ns() = next() private fun na(n: Int, offset: Int = 0): IntArray { return IntArray(n) { ni() + offset } } private fun nal(n: Int, offset: Int = 0): LongArray { val res = LongArray(n) for (i in 0 until n) { res[i] = nl() + offset } return res } private fun na2(n: Int, offset: Int = 0): Array { val a = Array(2){IntArray(n)} for (i in 0 until n) { for (e in a) { e[i] = ni() + offset } } return a } private inline fun debug(msg: () -> String) { if (isDebug) System.err.println(msg()) } private inline fun debug(a: LongArray) { debug { a.joinToString(" ") } } private inline fun debug(a: IntArray) { debug { a.joinToString(" ") } } private inline fun debug(a: BooleanArray) { debug { toString(a) } } private inline fun toString(a: BooleanArray) = run{a.map { if (it) 1 else 0 }.joinToString("")} private inline fun debugDim(A: Array) { if (isDebug) { for (a in A) { debug(a) } } } private inline fun debugDim(A: Array) { if (isDebug) { for (a in A) { debug(a) } } } private inline fun debugDim(A: Array) { if (isDebug) { for (a in A) { debug(a) } } } /** * 勝手にimport消されるのを防ぎたい */ private fun hoge() { min(1, 2) max(1, 2) abs(-10) } private inline fun assert(b: Boolean) = run{if (!b) throw AssertionError()} } fun main() { val out = java.io.PrintWriter(System.out) Solver(System.`in`, out).solve() out.flush() }