stuck at this problem. Help needed. Python preferred but i dont mind any other language

Description: Miriam is preparing to sail down Puzzle River. She needs to construct a raft out of special blocks. She has one of each block with width corresponding to the natural numbers (1,2, 3, ...) Blocks may only be attached to consecutive width blocks. Thus, block 3 can attach to 2 and 4 only. Help Miriam count all the ways to construct a raft of exactly the given width ' n " with the special blocks Input Format: Single number ' n ' representing the total width of the raft Example Input: Input Format: single number ' n ' representing the total width of the raft Example Input: 9 Output Format: Print the number of ways to construct a raft of width ' n ' Example Ouput: 2 Explanation: 2,3,4 and 4,5 are valid rafts with width 9