#!/usr/bin/perl

# By Craig Kelley -- using perl 5.8.8

use strict;
use warnings;

while (my $line = <STDIN>) {
   $line =~ s/\s+//g;
   my $level = 0;
   my $max = 0;
   for (my $i=0; $i<length($line); $i++) {
      my $char = substr($line, $i, 1);
      if ($char eq "(") {
	 $level++;
	 if ($level > $max) {
	    $max = $level;
	 }
      }
      if ($char eq ")") {
	 $level--;
	 if ($level < 0) {
	    # unbalanced
	    $i = length($line);
	 }
      }
   }
   if ($level != 0) {
      print "0\n";
   } else {
      print "$max\n";
   }
}