A number sequence is defined as following: S(1)=1, S(2)=11, S(3)=21, S(4)=1211, S(5)=111221, S(6)=312211, …… Now, we need you to calculate the length of S(n).
输入解释
The input consists of multiple test cases. Each test case contains one integers n. (1<=n<=30) n=0 signal the end of input.