#include <bits/stdc++.h>   using namespace std;   int main() {     int n, a[100], b[100], oa = 0, ob = 0, ore = 0;     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a[i] >> b[i];       if (a[i] % 2 == 1) oa++;       if (b[i] % 2 == 1) ob++;       if (a[i] % 2 == 1 && b[i] % 2 == 1) ore++;     }     if (oa % 2 == 0 && ob % 2 == 0)       cout << 0;     else if (oa % 2 == 1 && ob % 2 == 0 || oa % 2 == 0 && ob % 2 == 1 ||              oa - ore == 0 && ob - ore == 0)       cout << -1;     else       cout << 1;   }   