問題
Fibonacci sequence of numbers
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2
In a defined sequence.
Make a program that outputs the n-th Fibonacci sequence.
Input
N
Given the number N of the Fibonacci sequence to be determined in the first line.
Output
You should output the N-th of the Fibonacci sequence.
Constraint
Satisfies the following for all of the input and output case.
- 1 <= N <= 90
Input and output example
Input example Ⅰ
6
Output example Ⅰ
8
Input example Ⅱ
1
Output example Ⅱ
1
Input example Ⅲ
25
Output example Ⅲ
75025