Fibonacci Number
The Fibonacci numbers, commonly denoted F(n), form a sequence called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is:
F(0) = 0,F(1) = 1F(n) = F(n - 1) + F(n - 2), forn > 1
Given n, calculate F(n).
Example 1
Input
n = 2Output
1F(2) = F(1) + F(0) = 1 + 0 = 1.
Example 2
Input
n = 3Output
2F(3) = F(2) + F(1) = 1 + 1 = 2.
Constraints
- 0 <= n <= 30