public boolean cinGood(String str) {

        char []string = str.toCharArray();

        if (str.length()==2) {

            if (string[0] >= FIRST_TOP_COORD && string[0] <= FIRST_TOP_COORD+SIZE_OF_MATRIX/2-TOP_AND_LEFT_BORDER_SIZE) {

                if (string[1] >= FIRST_LEFT_COORD && string[1] <= FIRST_LEFT_COORD+SIZE_OF_MATRIX/2-DOWN_AND_RIGHT_BORDER_SIZE) {

                    return true;

                } else {

                    wrongInputMessage();

                    return false;

                }
            } else {

                wrongInputMessage();

                return false;
            }

        } else {

            wrongInputMessage();

            return false;
        }


    }