#include <bits/stdc++.h>

using namespace std;

int LeviCivitaSymbol(int a, int b, int c) {
    if (a == b || b == c || c == a) {
        return 0;
    } else {
        return (b - a + 3) % 3;
    }
}

int main() {
    int N;
    cin >> N;

    vector<int> As(2 * N + 1);
    for (int i = 0; i < 2 * N + 1; i++) {
        cin >> As[i];
    }

    int N_2 = N - 1;
    vector<int> As_2(2 * N - 1);
    for (int i = 0; i < 2 * N - 1; i++) {
        As_2[i] = LeviCivitaSymbol(As[i], As[i + 1], As[i + 2]);
    }

    vector<int> one, two;
    if (N_2 % 2 == 0) {
        one =  {1, 0, 2, 0};
        two =  {2, 0, 1, 0};
    } else {
        one =  {2, 0, 1, 0};
        two =  {1, 0, 2, 0};
    }

    bool flg1 = true;
    for (int i = 0; i < 2 * N_2 + 1; i++) {
        if (As_2[i] != one[i % 4]) {
            flg1 = false;
            break;
        }
    }
    if (flg1) {
        cout << 1 << endl;
        return 0;
    }
    
    bool flg2 = true;
    for (int i = 0; i < 2 * N_2 + 1; i++) {
        if (As_2[i] != two[i % 4]) {
            flg2 = false;
            break;
        }
    }
    if (flg2) {
        cout << 2 << endl;
        return 0;
    }

    cout << 0 << endl;
    return 0;
}