int IsShort;

        if(num1 < num2) {
            IsShort = num1;
        } else {
            IsShort = num2;
        }

        while (checkMarks < 3 || checkMarks > IsShort) {

                try {
                    checkMarks = Integer.parseInt(input.nextLine().trim());
                } catch (NumberFormatException e) {
                    System.out.println("Try again! It needs to be a number! 3 is the minimum and maximum is the amount of smaller side of board. " + "Height is: " + gameboardHeight +"." + " Width is: " + gameboardWidth + ".");
                    continue;
                }

                if (checkMarks < 3 || checkMarks > IsShort) {
                    System.out.println("Please give bigger number, 3 is the minimum and maximum is the amount of smaller side of board. " + "Height is: " + gameboardHeight +"." + " Width is: " + gameboardWidth + ".");
                }
            }

    return checkMarks;