Given an integer n representing number of vertices. Find out how many undirected graphs (not necessarily connected) can be constructed out of a given n number of vertices.

Example 1:
Input: 2
Output: 2
Example 2:
Input: 5
Output: 1024

Your Task:
Complete the function count() which takes an integer n as input and return the count of total number of graphs possible.

Expected Time Complexity: O(1)
Expected Space Complexity: O(1)

Constraints:
1<=n<=10

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