//********nikhiljugale007**********// #include<bits/stdc++.h> #include<iostream> #include<vector> #include<cstring> #include<algorithm> #include<set> #include<iterator> using namespace std; #define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0) #define ll long long #define v vector<ll int> #define it iterator it #define pb push_back #define f(a,b) for(long long int i=a;i<b;i++) #define fv(v) for(auto i=v.begin() ; i!=v.end();i++) #define min min_element #define max max_element #define hell 1000000007 int main(){ #ifndef ONLINE_JUDGE //Read input freopen("input.txt","r",stdin); //Write output freopen("output.txt","w",stdout); #endif int n; cin>>n; int arr[n][2]; int sumU = 0 , sumL = 0 ; for(int i=0;i<n;i++){ cin>>arr[i][0]>>arr[i][1]; sumU += arr[i][0]; sumL += arr[i][1]; } if(sumU%2==0 && sumL%2==0){ cout<<"0"<<endl; return 0; } else if(sumU%2==0 || sumL%2==0){ cout<<"-1"<<endl; return 0; } else{ for(int i=0;i<n;i++){ if((arr[i][0]%2==0) && (arr[i][1]%2!=0)){ cout<<"1"<<endl; return 0; } else if((arr[i][0]%2!=0) && (arr[i][1]%2==0)){ cout<<"1"<<endl; return 0; } } } cout<<"-1"<<endl; return 0; }