Given a positive integer N, find the last digit of the N^{th} term from the Fibonacci series.
Note: For N=0 you have to return 0.

Example 1:
Input:
N = 5
Output:
5
Explanation:
5th Fibonacci number is 5
Example 2:
Input:
N = 14
Output:
7
Explanation:
14th Fibonacci number is 377
It's last digit is 7
Your Task:
You don't need to read input or print anything. Your task is to complete the function fib() which takes an integer N as input parameter and returns the last digit of Nth Fibonacci number.
Expected Time Complexity: O(N)
Expected Space Complexity: O(1)

Constraints:
0 <= N <= 1000

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