For two given positive numbers a and b. Find a^b. Output your number modulus 10⁹+7.

Example 1:

Input: a = 1, b = 1
Output: 1
Explanation: 1¹ % (10⁹+7) = 1

â€‹Example 2:

Input: a = 2, b = 5
Output: 32
Explanation: 2⁵ % (10⁹+7) = 32

Your Task:
You don't need to read input or print anything. Your task is to complete the function power() which takes a, b as inputs, and returns the answer.

Expected Time Complexity: O(log b)
Expected Auxiliary Space: O(1)

Constraints:
1 ≤ a ≤ 10⁵
1 ≤ b ≤ 10¹⁶