#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> A(N * 2 + 1);
  for (int i = 0; i <= N * 2; i++){
    cin >> A[i];
  }
  bool ok = false;
  for (int i = 0; i <= N * 2 - 1; i++){
    if (A[i] == A[i + 1]){
      ok = true;
    }
  }
  for (int i = 0; i <= N * 2 - 3; i++){
    int x = (A[i + 1] - A[i] + 3) % 3;
    int y = (A[i + 2] - A[i + 1] + 3) % 3;
    int z = (A[i + 3] - A[i + 2] + 3) % 3;
    if (x == y && y == z){
      ok = true;
    }
  }
  for (int i = 0; i <= N * 2 - 3; i++){
    vector<bool> used(3, false);
    for (int j = 0; j < 4; j++){
      used[A[i + j]] = true;
    }
    for (int j = 0; j < 3; j++){
      if (!used[j]){
        ok = true;
      }
    }
  }
  if (ok){
    cout << 0 << endl;
  } else {
    for (int i = 0; i < 3; i++){
      vector<int> B(N * 2 + 1);
      for (int j = 0; j <= N * 2; j++){
        B[j] = (A[j] + i) % 3;
      }
      bool ok2 = true;
      for (int j = 0; j < N * 2; j++){
        if (abs(B[j + 1] - B[j]) >= 2){
          ok2 = false;
        }
      }
      if (ok2){
        swap(A, B);
        break;
      }
    }
    if (A[0] == 1){
      cout << 0 << endl;
    } else if (A[0] == 0){
      if (N % 2 == 1){
        cout << 1 << endl;
      } else {
        cout << 2 << endl;
      }
    } else {
      if (N % 2 == 0){
        cout << 1 << endl;
      } else {
        cout << 2 << endl;
      }
    }
  }
}