C :

#include<stdio.h>
#include<string.h>

int main()
{
	int i,sum;
	char a[1001];
	while(gets(a))
	{
		sum=0;
		for(i=0;a[i]!='B';i++)
		{
			if(a[i]=='(')
				sum++;
			if(a[i]==')')
				sum--;
		}
		printf("%d\n",sum);
	}
	return 0;
}

C++ :

#include<stdio.h>
#include<string.h>

int main()
{
	int i,sum;
	char a[1001];
	while(gets(a))
	{
		sum=0;
		for(i=0;a[i]!='B';i++)
		{
			if(a[i]=='(')
				sum++;
			if(a[i]==')')
				sum--;
		}
		printf("%d\n",sum);
	}
	return 0;
}

Pascal :

program p1021;
var i,j,k,n:longint;
    s:ansistring;
begin
  while not eof do
   begin
    readln(s);
    i:=0; j:=0;
    while i<length(s) do
      begin
       i:=i+1;
       if s[i]='(' then j:=j+1
       else if s[i]=')' then j:=j-1
       else if s[i]='B' then
             begin
               writeln(j);
               break;
             end;
      end;
   end;
end.

Java :

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		while(in.hasNext()){
			String s = in.nextLine();
			while(true){
				String tem = s.replaceAll("\\(\\)", "");
				if(tem.equals(s))break;
				else s = tem;
			}
			char[] cs = s.toCharArray();
			for(int i=0;i<cs.length;i++)
				if(cs[i]=='B')System.out.println(i);
		}
	}

}

Python :

import sys

for line in sys.stdin:
    data = line.split()[0]
    while data.find('()')!=-1:
          data = data.replace('()','')
    print data.find('B')