import java.io.BufferedReader;
import java.io.InputStreamReader;
class Main
{
{
String[] params1
= bufferedReader.
readLine().
split(" "); int max_page_size = 210;
boolean[][] squares = new boolean[max_page_size][max_page_size];
for (int i = 0; i < max_page_size; ++i){
for (int j = 0; j < max_page_size; ++j){
squares[i][j] = false;
}
}
int n;
for (int i = 0; i < n; ++i){
String[] params2
= bufferedReader.
readLine().
split(" "); int x, y;
squares[x + max_page_size / 2][y + max_page_size / 2] = true;
}
int perimiter = 0;
for (int i = 0; i < max_page_size; ++i){
for (int j = 0; j < max_page_size; ++j){
if (squares[i][j]){
perimiter += (!squares[i + 1][j] ? 1 : 0) + (!squares[i - 1][j] ? 1 : 0) + (!squares[i][j + 1] ? 1 : 0) + (!squares[i][j - 1] ? 1 : 0);
}
}
}
int max = 0;
for (int j = 1; (perimiter - 2 * j) / 2 > 0; ++j){
int i = (perimiter - 2 * j) / 2;
if (i * j - n > max) {
max = i * j - n;
}
}
}
}
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