#include <bits/stdc++.h>

using namespace std;
ifstream fin("paranteze2.in");
ofstream fout("paranteze2.out");

char s[260];
int st[1000];
int n, top;
int main()
{
    int i, x;
    fin >> s;
    for(i = 0;s[i];i++)
    {
        if(s[i] == '(')
            st[++top] = -1;
        else
        {
            if(st[top]> 0)
            {
                x = st[top];
                top--;
            }
            else
                x = 0;
            ///acum in vf stivei este sigur -1;
            top--;
            x++;
            ///cazul 1 stiva e vida sau paranteza in vf
            if(top == 0 || st[top] == -1)
                st[++top] = x;
            ///caz 2 in vf stivei este un nr
            else
                st[top] = max(x, st[top]);
        }
    }
    fout << st[top];
    return 0;
}