Description

In Euclidean geometry, the sum of interior angles of an n-sided polygon is (n-2)×180°.
Given (n-1) interior angles of an n-sided polygon, write a program to calculate the remaining unknown interior angle.

Input Format

The first line contains a single integer n (3≤n≤20).
The second line contains (n-1) positive integers representing the known interior angles, separated by spaces. The input guarantees that the polygon is valid.

Output Format

Output a single positive integer representing the unknown interior angle.

Sample

3
45 60

75