Letter Sum

Problem Description

Xiaoyang invented a new kind of cipher. For each lowercase English letter, that letter represents a positive integer equal to its position in alphabetical order — for example, a represents $1$, b represents $2$. For each uppercase English letter, that letter represents a negative integer equal to the opposite of its ASCII code — for example, A represents the negative integer $-65$. Xiaoyang used this rule to encrypt an integer and obtained a string made of uppercase and lowercase letters; the sum of the numbers represented by each letter in the string equals the original integer before encryption. For example, aAc corresponds to the original integer $1+(-65)+3=-61$.

Given a string, compute what the original integer before encryption was.

Input Format

The first line contains a positive integer $n$, the number of letters in the string.

The second line contains a string T made of uppercase and lowercase letters, representing the encrypted string.

Output Format

Output one line containing an integer: the original integer before encryption.

Sample Input

3
aAc

Sample Output

-61

Sample Explanation

For the string aAc, the letter a corresponds to $1$, the letter A corresponds to $-65$, and the letter c corresponds to $3$; the sum is $1 + (-65) + 3 = -61$, so the output is $-61$.

Constraints

For all test data, it is guaranteed that $1 \le n \le 10^5$.