#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define Mp make_pair
#define sep ' '
#define endl '\n'
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define kill(res) cout << res << '\n', exit(0);
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 2e6 + 50;
const ll Mod = 1e9 + 7;
int n, m, k, vas[N], L[N], R[N];
string s;
vector<int> adj[N];
void dfs(int v, int p = 0){
vector<int> ch;
for(int u: adj[v]){
if(u != p){
dfs(u, v); ch.pb(u);
}
}
if(ch.empty()){
L[v] = 0; R[v] = 0;
return;
}
if(vas[v]){
R[v] = min(R[ch[0]], R[ch[1]]);
L[v] = L[ch[0]] + L[ch[1]] + 1;
}
else{
L[v] = min(L[ch[0]], L[ch[1]]);
R[v] = R[ch[0]] + R[ch[1]] + 1;
}
}
int main(){
fast_io;
cin >> s;
m = s.size();
vector<int> path;
for(int i = 0; i < m;){
if(s[i] == 'm'){
int v = ++n;
if(s[i+1] == 'a') vas[v] = 1;
if(!path.empty()){
int u = path.back();
adj[u].pb(v);
adj[v].pb(u);
}
path.pb(v);
i += 4;
}
else if(s[i] == ',') i++;
else if(s[i] == '?'){
int v = ++n;
if(!path.empty()){
int u = path.back();
adj[u].pb(v);
adj[v].pb(u);
}
i++; k++;
}
else{
path.pop_back(); i++;
}
}
dfs(1);
cout << max(0, k - L[1] - R[1]);
}
