题目描述

The Fibonacci Numbers{0,1,1,2,3,5,8,13,21,34,55...} are defined by the recurrence: F0=0 F1=1 Fn=Fn-1+Fn-2,n>=2 Write a program to calculate the Fibonacci Numbers.

输入格式

Each case contains a number n and you are expected to calculate Fn.(0<=n<=30) 。