Adjacent Tokens Scoring

A row has n cells; each cell has a value points[i], and its state is T if it holds a token or E if it is empty. Each T cell contributes its own value; each pair of adjacent T cells contributes an extra 1 point. Find the total score.

The rules, constraints, and two public examples correspond to the original Barclays problem.

输入格式

The first line contains n (1 ≤ n ≤ 100); the second line contains n integers points[i] (1 ≤ points[i] ≤ 1000); the third line contains a string of length n consisting only of E and T.

输出格式

Output a single integer, the answer.

样例 1

输入：

5
3 2 1 2 2
ETTTE

输出：

7

样例 2

输入：

4
2 2 2 2
TTTT

输出：

11

样例 3

输入：

5
3 4 5 2 3
TEETT

输出：

9

样例说明

In example 1 the tokens are in cells 0, 3, 4; the base score is 3+2+3=8, and the adjacent pair (3,4) adds 1, for a total of 9.