#pragma GCC ta g("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define DEBUG
#ifdef DEBUG
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    os << '{';
    for(int i = 0; i < (int)v.size(); i++) {
        if(i) { os << ','; }
        os << v[i];
    }
    os << '}';
    return os;
}
void debugg() { cerr << endl; }
template <class T, class... Args>
void debugg(const T &x, const Args &... args) {
    cerr << " " << x;
    debugg(args...);
}
#define debug(...)                                                             \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]: ", debugg(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef pair<ll,ll> P;
typedef pair<int,int> pii;
typedef vector<P> vpl;
typedef tuple<ll,ll,ll> tapu;
#define rep(i,n) for(int i=0; i<(n); i++)
#define REP(i,a,b) for(int i=(a); i<(b); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<typename T1,typename T2> inline bool chmin(T1 &a,T2 b){
	if(a>b){
		a = b; return true;
	}
	else return false;
}
template<typename T1,typename T2> inline bool chmax(T1 &a,T2 b){
	if(a<b){
		a = b; return true;
	}
	else return false;
}
template<typename T> inline void print(T &a){
    int sz = a.size();
    for(auto itr = a.begin(); itr != a.end(); itr++){
		cout << *itr;
        sz--;
        if(sz) cout << " ";
	}
    cout << "\n";
}
template<typename T1,typename T2> inline void print2(T1 a, T2 b){
	cout << a << " " << b << "\n";
}
template<typename T1,typename T2,typename T3> inline void print3(T1 a, T2 b, T3 c){
	cout << a << " " << b << " " << c << "\n";
}
void mark() {cout << "#" << "\n";}
ll pcount(ll x) {return __builtin_popcountll(x);}
//#include <atcoder/maxflow>
//using namespace atcoder;
const int inf = (1<<30)-1;
const ll linf = 1LL<<61;
const int MAX = 510000;
int dy[8] = {0,1,0,-1,1,-1,-1,1};
int dx[8] = {-1,0,1,0,1,-1,1,-1};
const double pi = acos(-1);
const double eps = 1e-9;
const int mod = 1e9 + 7;
//const int mod = 998244353;

vl A;
void f(int k){
    if(k == 0){
        int n = A.size();
        vl a = A;
        while((int)a.size() > 1){
            n = a.size();
            vl b(n-2);
            rep(i,n-2){
                if(a[i+1]%3 == (a[i]+1)%3 && a[i+2]%3 == (a[i+1]+1)%3){
                    b[i] = 1;
                }else if(a[i+1]%3 == (a[i]+2)%3 && a[i+2]%3 == (a[i+1]+2)%3){
                    b[i] = 2;
                }else{
                    b[i] = 0;
                }
            }
            a = b;
        }
        if(a[0] != 0){
            debug(A,a[0]);
        }
    }else{
        rep(i,3){
            A.push_back(i);
            f(k-1);
            A.pop_back();
        }
    }
}

int main(){
    int n; cin >> n;
    //f(n); 実験
    int N = n*2+1;
    vl a(N); rep(i,N) cin >> a[i];
    if(a[0] == a[1]){
        cout << 0 << endl;
        return 0;
    }
    bool up = (a[0]+1)%3 == a[1];
    for(int i=0; i<N-1; i+=2){
        if(up){
            if((a[i]+1)%3 == a[i+1] && (a[i+1]+1)%3 == a[i+2]){
                up = false;
                continue;
            }
            cout << 0 << endl;
            return 0;
        }else{
            if(a[i] == (a[i+1]+1)%3 && a[i+1] == (a[i+2]+1)%3){
                up = true;
                continue;
            }
            cout << 0 << endl;
            return 0;
        }
    }
    if(!up) cout << 1 << endl;
    else cout << 2 << endl;
}