#include <iostream>
using namespace std;
 
#define MAX_PAGE_SIZE 210
 
int squares[MAX_PAGE_SIZE][MAX_PAGE_SIZE];
 
int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i){ int x, y; cin >> x >> y;
        squares[x + MAX_PAGE_SIZE / 2][y + MAX_PAGE_SIZE / 2] = 1;
    }
    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] + !squares[i - 1][j] + !squares[i][j + 1] + !squares[i][j - 1];
            }
        }
    }
    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;
        }
    }
    cout << max;
    return 0;
}

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3
1 2
2 1
3 1