14989 번 : Booming Business 
 14989 번 
 14989 번 - Booming Business 
 You are an expert in bonsai , the Japanese art of cultivating small trees in small containers . Every year , you win the Bonsai Association ’ s Pruning Competition ( BAPC ) . With all this talent , it would be a shame not to turn your hobby into your job . Recently , you have rented a small store where you will sell your creations . Now you need to make a window display to draw in customers . Of course , you would like to grow the most impressive tree that will fit the window , but the window is only so tall , and the floor of the display can only bear so much weight . Therefore , you want a tree that is exactly so tall and so heavy that it can fit in your window . 
 Being an expert , you know that by definition a bonsai tree consists of a single branch , with 0 or more smaller bonsai trees branching off from that branch . 
 Figure 1 : Four distinct examples of bonsai trees . 
 The height and weight of a bonsai tree can be carefully determined . A tree ’ s weight is equal to the number of branches that appear in it . The weights of the trees in Figure 1 are 1 , 4 , 6 and 6 , respectively . A tree ’ s height is equal to the length of the longest chain of branches from the root to the top of the tree . The heights of the trees in Figure 1 are 1 , 2 , 3 and 3 , respectively . 
 To make the most use of your window , you want to produce a bonsai tree of the precise height and weight that it can support . To get an idea of the number of options available to you , you would like to know how many different trees you could possibly grow for your store . Given a height and a weight , can you determine the number of trees with exactly that height and weight ? Because the number may be very large , you may give your answer modulo 1 , 000 , 000 , 007 . 
 A single line containing two integers , h and w , with 1 ≤ h , w ≤ 300 . 
 Output a single line containing a single integer , the number of bonsai trees of height h and weight w , modulo 109 + 7 . 
 573689752 
 ACM - ICPC > Regionals > Europe > Northwestern European Regional Contest > Benelux Algorithm Programming Contest > BAPC 2017 Preliminaries B 번