#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int s[550], t[550];
int b[550][550];
int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s[i];
	}
	for (int i = 0; i < n; i++) {
		cin >> t[i];
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			b[i][j] = 2;
		}
	}
	int co = 0;
	for (int i = 0; i < n; i++) {
		if (s[i] == 0) {
			for (int j = 0; j < n; j++) {
				b[i][j] = 0;
			}
		}
		if (s[i] == 2) {
			int c = n;
			for (int j = 0; j < n; j++) {
				if (b[i][j] == 1) {
					c--;
				}
				b[i][j] = 1;
			}
			co += c;
		}
	}
	for (int i = 0; i < n; i++) {
		if (t[i] == 0) {
			for (int j = 0; j < n; j++) {
				b[j][i] = 0;
			}
		}
		if (t[i] == 2) {
			int c = n;
			for (int j = 0; j < n; j++) {
				if (b[j][i] == 1) {
					c--;
				}
				b[j][i] = 1;
			}
			co += c;
		}
	}
	set<int> h, w;
	for (int i = 0; i < n; i++) {
		if (s[i] == 1) {
			bool bo = true;
			for (int j = 0; j < n; j++) {
				if (b[i][j] == 1) {
					bo = false;
				}
			}
			if (bo) {
				h.insert(i);
			}
		}
	}
	for (int i = 0; i < n; i++) {
		if (t[i] == 1) {
			bool bo = true;
			for (int j = 0; j < n; j++) {
				if (b[j][i] == 1) {
					bo = false;
				}
			}
			if (bo) {
				w.insert(i);
			}
		}
	}
	cout << co + max(h.size(), w.size()) << endl;
}