Find the sum of values for the function

in some integers.

Input

First line contains the number of points n (1 ≤ n ≤ 50). Next line contains n integers x1, x2, ..., xn - the points where the function must be calculated and summed up (0 ≤ |xi| ≤ 109).

Output

Print one number - the sum of function values f(x) at given points. The answer is correct if its accuracy is no less than 10-9.