import java.util.*;
import java.lang.*;

public class Main {
    public static void main(String[] args) {
        new Main().solve();
    }

    public void solve() {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[][] a = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = scanner.nextInt();
            }
        }

        int answer = findMaxOnesSquare(a);
        System.out.printf("Max ones rectangle square is %d.\n", answer);
    }

    private int findMaxOnesSquare(int[][] a) {
        int n = a.length;
        int[] onesUp = new int[n];
        int answer = 0;

        for (int row = 0; row < n; row++) {
            Stack<Integer> prevColumns = new Stack<>();

            for (int column = 0; column < n; column++) {
                if (a[row][column] == 1) {
                    onesUp[column]++;
                } else {
                    onesUp[column] = 0;
                }

                int curHeight = onesUp[column];
                while (!prevColumns.isEmpty()) {
                    int prevPos = prevColumns.peek();
                    if (onesUp[prevPos] < curHeight) {
                        break;
                    } else {
                        int curMax = curHeight * (column - prevPos + 1);
                        answer = Math.max(answer, curMax);

                        prevColumns.pop();
                    }
                }

                prevColumns.push(column);
            }

            while (!prevColumns.isEmpty()) {
                int prevPos = prevColumns.pop();
                int curMax = onesUp[prevPos] * (n - prevPos);
                answer = Math.max(answer, curMax);
            }
        }

        return answer;
    }
}