#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T& container, string separator = " ", string finish = "\n"){
for(auto item: container) cout << item << separator;
cout << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
const int N = 2e6 + 69;
int cnt = 0, pos = 0;
int n = 0;
int type[N];
pair<int, int> graph[N];
void dfs(string &s, int u){
graph[u] = {-1, -1};
if (s[pos] == 'm'){
type[u] = (s[pos+1] == 'a');
pos += 3;
pos++;
graph[u].first = ++cnt;
dfs(s, cnt);
pos++;
graph[u].second = ++cnt;
dfs(s, cnt);
pos++;
}
else{
pos++;
n++;
}
}
int sz[N];
pair<int,int> go(int u){
if (graph[u] == make_pair(-1, -1)){
sz[u] = 1;
return make_pair(1, 1);
}
pair<int, int> L = go(graph[u].first), R = go(graph[u].second);
sz[u] = sz[graph[u].first] + sz[graph[u].second];
if (type[u] == 0){ // min
int mi = min(L.first, R.first);
int ma = L.second + R.second - 1;
return make_pair(mi, ma);
}
else{ // max
int mi = sz[u] - ((sz[graph[u].first] - L.first) + (sz[graph[u].second] - R.first));
int ma = max(L.second + sz[graph[u].second], R.second + sz[graph[u].first]);
return make_pair(mi, ma);
}
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
clock_t start = clock();
string s; cin >> s;
dfs(s, 0);
pair<int, int> ans = go(0);
cout << ans.second - ans.first + 1 << "\n";
cerr << "Time elapsed: " << clock() - start << "ms!\n";
return 0;
}
