#include<iostream>
#include<stack>
using namespace std;

stack<string> s; string a;

int main()
{
	for(int i = 0; ; ++i) {
		cin>>a[i];
		if(a[i] == '*') break;
		if(a[i] == '(') s.push(a);
		else s.pop();
	}
	cout<<s.size()<<endl;
	return 0;
}