Codeforces Round #205 (Div. 2) A Domino

// Codeforces Round #205 (Div. 2) A Domino
// Problems: http://codeforces.com/contest/353/problem/A

import java.io.*;
import java.math.*;
import java.util.*;

import org.omg.CORBA.Environment;

//Codeforces
public class MainCodeforces1 {
private static MyScanner in;
private static PrintStream out;
private static boolean LOCAL_TEST = false;

private static void solve() throws IOException
{
int n = in.nextInt();
int[] x = new int[n];
int[] y = new int[n];
int sum = 0;
int sumx = 0;
int sumy = 0;
for (int i = 0; i < n; i++) {
x[i] = in.nextInt();
y[i] = in.nextInt();
sumx += x[i];
sumy += y[i];
}
sum = sumx + sumy;
if (sum % 2 == 1)
out.println(-1);
else {
if (sumx % 2 == 0 && sumy % 2 == 0)
out.println(0);
else {
for (int i = 0; i < n; i++) {
if ((x[i] % 2 == 1 && y[i] % 2 == 0) ||
(x[i] % 2 == 0 && y[i] % 2 == 1)) {
out.println(1);
return;
}
}
out.println(-1);
}
}
}

public static void main(String[] args) throws IOException {
// helpers for input/output
out = System.out;
try {
String cname = System.getenv("COMPUTERNAME");
if (!cname.equals(""))
LOCAL_TEST = true;
} catch (Exception e) {
}
if (LOCAL_TEST) {
in = new MyScanner("E:\\zin.txt");
}
else {
boolean usingFileForIO = false;
if (usingFileForIO) {
// using input.txt and output.txt as I/O
in = new MyScanner("input.txt");
out = new PrintStream("output.txt");
}
else {
in = new MyScanner();
out = System.out;
}
}

solve();
}

// =====================================
static class MyScanner {
BufferedReader bufReader;
StringTokenizer strTok;

public MyScanner() throws IOException
{
bufReader = new BufferedReader(new InputStreamReader(System.in));
strTok = new StringTokenizer("");
}

public MyScanner(String inputFile) throws IOException {
bufReader = new BufferedReader(new InputStreamReader(
new FileInputStream(
inputFile)));
strTok = new StringTokenizer("");
}

String GetNextToken() throws IOException {
if (!strTok.hasMoreTokens())
strTok = new StringTokenizer(bufReader.readLine());
return strTok.nextToken();
}

public int nextInt() throws IOException {
return Integer.valueOf(GetNextToken());
}

public long nextLong() throws IOException {
return Long.valueOf(GetNextToken());
}

public double nextDouble() throws IOException {
return Double.valueOf(GetNextToken());
}

public String nextString() throws IOException {
return GetNextToken();
}

public String nextLine() throws IOException {
return bufReader.readLine();
}

public int countTokens() {
return strTok.countTokens();
}

public boolean hasMoreTokens() {
return strTok.hasMoreTokens();
}
}

}