public class LargestRectangle {

    public static void main(String[] args) {

//        Scanner scanner = new Scanner(System.in);
//        String[] inputLine = scanner.nextLine().split(",");
//        String[][] matrix = new String[20][inputLine.length - 1];
//        int numberRows = 0;
//
//        for (int row = 0; row < 20; row++) {
//            for (int col = 0; col < inputLine.length - 1; col++) {
//                matrix[row][col] = inputLine[col + 1];
//            }
//            inputLine = scanner.nextLine().split(",");
//            if (inputLine[0].equals("END")) {
//                numberRows = row + 1;
//                break;
//            }
//        }
        String[][] matrix =
                {
                        {"xx", "a", "a", "a", "a", "a", "a"},
                        {"a", "a", "z", "z", "a", "php", "a"},
                        {"a", "a", "x", "x", "a", "a", "a"},
                        {"xx", "a", "sql", "a", "a", "js", "a"},
                        {"xx", "a", "a", "a", "a", "a", "a"},
                        {"xx", "a", "z", "z", "a", "php", "w"}
                };


        int maxFoundElements = 0;
        int foundElements = 1;
        for (int row = 0; row < 6; row++) {
            for (int col = 0; col < matrix[0].length - 1; col++) {

                for (int moveRight = col; moveRight < matrix[0].length - 1; moveRight++) {
                    if (foundElements > maxFoundElements) {
                        maxFoundElements = foundElements;
                        foundElements = 1;
                    }
                    if (matrix[row][moveRight].equals(matrix[row][moveRight + 1])) {
                        foundElements++;
                        for (int moveDown = row; moveDown < 6 - 1; moveDown++) {
                            if (matrix[moveDown][moveRight + 1].equals(matrix[moveDown + 1][moveRight + 1])) {
                                foundElements++;
                                for (int moveLeft = moveRight + 1; moveLeft > 0; moveLeft--) {
                                    if (matrix[moveDown + 1][moveLeft].equals(matrix[moveDown + 1][moveLeft - 1])) {
                                        foundElements++;
                                        for (int moveUp = moveDown + 1; moveUp > 0; moveUp--) {
                                            if (matrix[moveUp][moveLeft - 1].equals(matrix[moveUp - 1][moveLeft - 1])) {
                                                foundElements++;
                                            } else {
                                                moveUp = 0;
                                                foundElements--;
                                            }
                                        }
                                    } else {
                                        moveLeft = 0;
                                        foundElements--;
                                    }
                                }
                            } else {
                                moveDown = 6 - 1;
                                foundElements--;
                            }
                        }
                    } else {
                        moveRight = matrix[0].length - 1;
                        foundElements--;
                    }
                }
            }
        }

        System.out.println(maxFoundElements);
    }
}