public class L0085 {
    public static void main(String[] args) throws Exception {
        char[][] g = {{'0','0','0','0','0','0','1'},{'0','0','0','0','1','1','1'},{'1','1','1','1','1','1','1'},{'0','0','0','1','1','1','1'}};
        System.out.print(maximalRectangle(g));
    }

    public static int maximalRectangle(char[][] matrix) {
        int x, y;
        int i,j;
        int row = matrix.length;
        int col;
        if (row == 0){
            return 0;
        }
        else{
            col = matrix[0].length;
        } 
        int sum = 0;
        for (x = 0; x < row; x++) {
            for (y = 0; y < col; y++) {
                if (matrix[x][y] == '1') {
                    i = x;
                    j = y;
                    int a = 1;
                    int b = 1;
                    int k;
                    int sum2 = 0;
                    while (i < row) {
                        if (matrix[i][y] == '1') { //竖着往下遍历
                            i++;
                            a = i - x;
                            j = y + 1;
                            int temp = j;
                            while (j < col) {
                                for (k = x; k < i; k++){               
                                    if (matrix[k][j] == '0'){ //遇到横的为零
                                        temp = j;
                                        b = temp - y;
                                        j = col;
                                        break;
                                    }
                                    else{
                                        temp = j + 1;
                                    }
                                }
                                j++;
                            }
                            b = temp - y;
                            if (a*b > sum2){
                                sum2 = a*b;
                            }
                            
                        }
                        else{
                            break;
                        }
                    }
                    if (sum2 > sum){
                        sum = sum2;
                    }
                }
            }
        }
        return sum;

    }
}