#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(n); i++)



int main(){
  int N; cin >> N;
  vector<int> A(N*2+1);
  for(auto& a : A) cin >> a;

  int xx = 0;

  rep(t, 4+N%4){
    if(A.size() == 1){ cout << A.front() << endl; return 0; }
    rep(i,A.size()-2){
      int v = 0;
      if((3+A[i+1]-A[i]) % 3 == 1) if((3+A[i+2]-A[i+1]) % 3 == 1) v = 1;
      if((3+A[i+1]-A[i]) % 3 == 2) if((3+A[i+2]-A[i+1]) % 3 == 2) v = 2;
      A[i] = v;
    }
    A.pop_back();
    A.pop_back();
    if(A.size() == 1){ cout << A.front() << endl; return 0; }
    //rep(i,xx) cout << " ";
    //for(auto a : A) cout << a << " "; cout << endl;
    xx += 2;
  }

  rep(i,A.size()-1) if(A[i] == A[i+1]){ cout << 0 << endl; return 0; }
  if(A[0] == 0){ cout << 0 << endl; return 0; }
  cout << A[A.size()/2] << endl;

  return 0;
}




struct ios_do_not_sync {
    ios_do_not_sync() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;