Algorithm title: UVA 10862

Asif is a student of East West University and he are currently working for the Ewuisp to meet him relatively high tuition F Ees. One day, as a part's his job, he is instructed to connect cable wires to N houses. All of the houses lie in a straight line. He wants the "minimum number of cable wires required to complete his task such" all the houses receive the Cable service. A house can either get the "connection" from the main transmission center or it can be get it from a house to its immediate lef T or right provided the latter house is already getting the service.

You are are to write a program that determines the number of different combinations of the cable wires this is possible so tha T every house receives the service.

Example: If There are two houses then 3 combinations are possible as shown in the figure.

Figure:circles represent the transmission center and the small rectangles represent the houses.

Input

Each line of input contains a positive integer N (n<=2000). The meaning of N is described in the above paragraph. A value of 0for N indicates the "end of" input which should not to be processed.

Output

For each line of input in have to output, on a single line, the number of possible arrangements. You can safely assume so this number would have less than 1000.

Sample Input