It is known that a, b, c, and d are positive integers, and a is less than 4b, b is less than 3c, and c is less than 2d. If d is less than 100, what is the maximum possible value of a?
已知a、b、c、d是正整数，并且a小于4b，b小于3c，c小于2d，如果d小于100，那么a的最大可能值是多少．
<result>2_359</result>