Problem Statement: Calculate Fibonacci Number

Objective

Write a function calculateFibonacci that calculates the nth Fibonacci number. A Fibonacci number is a number that appears in the Fibonacci sequence, where each number is the sum of the two preceding ones, starting from 0 and 1.

Function Signature

function calculateFibonacci(n)

Input

• n (int): A non-negative integer to calculate the nth Fibonacci number.

Output

• Returns the nth Fibonacci number.

Examples

• Input: n = 5

  • Output: 5
  • Explanation: The 5th Fibonacci number is 5 (0, 1, 1, 2, 3, 5).

• Input: n = 4 Output: 3 Explanation: The 4th Fibonacci number is 3 (0, 1, 1, 2, 3).

• Input: n = 13

  • Output: 233
  • Explanation: The 13th Fibonacci number is 233 (0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233).

Constraints

• 0 <= n <= 10^4

Note

The Fibonacci sequence starts with Fibonacci(0) = 0, Fibonacci(1) = 1.