#include <bits/stdc++.h>

using namespace std;

using ll = long long;

constexpr char newl = '\n';

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vector<int> s(n);
    bool fs2 = false;
    int cnts1 = 0;
    for (int i = 0; i < n; i++) {
        cin >> s[i];
        if (s[i] == 2) fs2 = true;
        cnts1 += (s[i] == 1);
    }

    vector<int> t(n);
    bool ft2 = false;
    int cntt1 = 0;
    for (int i = 0; i < n; i++) {
        cin >> t[i];
        if (t[i] == 2) ft2 = true;
        cntt1 += (t[i] == 1);
    }
    if (fs2) cntt1 = 0;
    if (ft2) cnts1 = 0;

    int ans = max(cntt1, cnts1);
    for (int i = 0; i < n; i++) {
        if (s[i] == 0) continue;
        if (s[i] == 2) {
            ans += n;
            continue;
        }

        for (int j = 0; j < n; j++) {
            if (t[j] == 2) ++ans;
        }
    }
    cout << ans << newl;

    return 0;
}