#include <bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
#define fs first
#define sc second
string s;
int meow = 0;
pii f(int st, int ed) {
if (st == ed) {
meow++;
return {0,0};
}
int complace = st, now = 0;
for (int i = st; i < ed; i++) {
if (s[i] == '(') now++;
if (s[i] == ')') now--;
if (s[i] == ',' and now==1) complace = i;
}
pii p1 = f(st+4, complace-1);
pii p2 = f(complace+1, ed-1);
if (s[st + 1]=='a') return {p1.fs+p2.fs+1, min(p1.sc,p2.sc)};
else return {min(p1.fs,p2.fs), p1.sc+p2.sc+1};
}
int main () {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> s;
pii p = f(0, s.size()-1);
cout << meow - p.fs - p.sc << '\n';
}
