#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
#include <ctime>
#include <bitset>
#pragma warning(disable:4996) 

#define ATCODER
#ifdef ATCODER
#include <atcoder/all>
#endif

typedef long long ll;
typedef unsigned long long ull;
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define LINF3 1000000000000
#define INF 2140000000
//const long long MOD = 1000000007;
const long long MOD = 998244353;

using namespace std;
#ifdef ATCODER
using namespace atcoder;
#endif



void solve()
{
    int n;
    scanf("%d", &n);
    vector<int> a(n * 2 + 1);
    for (int i = 0; i < n*2+1; i++) {
        scanf("%d", &a[i]);
    }
    if (n >= 2) {
        printf("0\n");
    }
    else {
        if ((a[1] - a[0] + 3) % 3 == 1 && (a[2] - a[1] + 3) % 3 == 1) {
            printf("1\n");
        }
        else if ((a[1] - a[0] + 3) % 3 == 2 && (a[2] - a[1] + 3) % 3 == 2) {
            printf("2\n");
        }
        else {
            printf("0\n");
        }
    }

    return;
}

int main()
{
#if 1
    solve();
#else
    int T, t;
    scanf("%d", &T);
    for (t = 0; t < T; t++) {
        //printf("Case #%d: ", t + 1);
        solve();
    }
#endif
    return 0;
}