#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}



//  rainy ~ 雨に打たれて ~
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int N;
	cin>>N;
	vector<int> p(N*2+1);
	rep(i,N*2+1) cin>>p[i];
	rep(k,min(N,100)){
		vector<int> q(p.size()-2);
		rep(i,p.size()-2){
			if((p[i+2]+p[i]-2*p[i+1]+9)%3==0) q[i]=(3+p[i+1]-p[i])%3;
		}
		p=q;
	}
	int m=p.size();
	if(m==1) cout<<p[0]<<"\n";
	else{
		int J=1;
		rep(i,m/2+1){
			if(p[i*2]==0) J=0;
		}
		cout<<J*p[m-1]<<"\n";
	}
}