#### Prep 3

You've made it to the weekend, and you're ready to sleep! While trying to fall asleep, a nagging voice repeatedly commands you to do your math homework first. Since you want to sleep as soon as possible, you decide to do the problems super quickly. But there's a problem — your math teacher thought it was a funny joke to give you tons of super easy problems. The teacher also thought it was funny to replace `+`

signs with the character `P`

and `-`

signs with the character `M`

. Instead of wasting your time solving each one by hand, you decide to write a program to solve them. The questions will only involve subtraction and addition, and have up to terms with all numbers greater than and less than or equal to .

#### Input Specification

Line 1: The equation, a sequence of numbers, `P`

, and `M`

. Each term will be space separated from each other character. The equation will be terminated by `=`

. There will be at least one term in the sequence.

#### Output Specification

Output one integer, the solution (right side) of the equation.

#### Sample Input

`5 P 13 P 27 M 35 =`

#### Sample Output

`10`

## Comments

Ah... Time to pull out the good old snake again...

Is the reason your math teacher is a troll because she knows Python?