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

string str;
stack<int> nums;
stack<char> ops;

void getNumbers(int &i)
{
    int number = 0;
    while (str[i] == 'x')
    {
        number++;
        i++;
    }
    nums.push(number);
}

void calc()
{
    char op = ops.top();
    ops.pop();
    int a = nums.top();
    nums.pop();
    int b = nums.top();
    nums.pop();
    if (op == '|')
    {
       // printf("%d|%d\n", a, b);
        nums.push(max(a, b));
    }
    else
    {
       // printf("%d&%d\n", a, b);
        nums.push(a+b);
    }
}

int main()
{
    cin >> str;
    str = '(' + str + ')';
    for (int i = 0; i < str.size(); ++i)
    {
        if (str[i] == '(')
        {
            if (i-1 > 0 && (str[i-1] == 'x' || str[i-1] == ')'))
            {
                while (ops.top() == '&')
                    calc();
                ops.push('&');
            }
          ops.push('(');  
        }
        else if (str[i] == 'x')
        {
            if (str[i-1] == ')')
            {
                while (ops.top() == '&')
                    calc();
                ops.push('&'); 
            }
            getNumbers(i);
            i--;

        }
        else if (str[i] == '|')
        {
            while (ops.top() != '(')
                calc();
            ops.push('|');
        }
        else
        {
            while (ops.top() != '(')
                calc();
            ops.pop();
        }
    }
    printf("%d", nums.top());
    return 0;
}