#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int>A(2*N+1);
    for(int i = 0; i <= 2*N; i++) {
        cin >> A[i];
    }
    if(2*N+1 == 3) {
        vector<vector<int>>base = {{0,1,2},{1,2,0},{2,0,1}};
        if(A == base[0] || A == base[1] || A == base[2]) {
            cout << 1 << endl;
        }
        else {
            base = {{2,1,0},{1,0,2},{0,2,1}};
            if(A == base[0] || A == base[1] || A == base[2]) {
                cout << 2 << endl;
            }
            else {
                cout << 0 << endl;
            }
        }
        return 0;
    }
    int f = A[0] != 0;
    for(int i = 1; i <= 2*N; i += 2) {
        if(A[i] != 0) {
            f = 0;
        }
    }
    if(f == 0) {
        cout << 0 << endl;
    }
    else {
        for(int i = 2; i <= 2*N; i += 2) {
            if(A[i] == 0 || A[i-2] == A[i]) {
                f = 0;
            }
        }
        if(f == 0) {
            cout << 0 << endl;
        }
        else {
            if(N%2 == A[0]%2) {
                cout << 2 << endl;
            }
            else {
                cout << 1 << endl;
            }
        }
    }
}