#include <bits/stdc++.h>
using namespace std;
vector<int> type, l, r;
vector<vector<int>> adj;
vector<int> leaves;
void dfs(int cur, int p) {
if (type[cur] == -1) {
leaves[cur] = 1;
return;
}
for (auto e : adj[cur]) {
if (e != p) {
dfs(e, cur);
leaves[cur] += leaves[e];
}
}
int lc = adj[cur][1];
int rc = adj[cur][2];
if (type[cur] == 1) {
// max
l[cur] = l[lc]+l[rc];
r[cur] = max(r[lc]+leaves[rc], r[rc]+leaves[lc]);
}
else {
// min
l[cur] = min(l[lc], l[rc]);
r[cur] = r[lc]+r[rc]-1;
}
}
int main() {
string s;
getline(cin, s);
int n = 0, q = 0;
for (int i = 0; i < s.length(); i++) {
if (s[i] == 'm') {
n++;
i += 3;
}
else if (s[i] == '?') {
n++;
i++;
q++;
}
}
adj.resize(2);
type.resize(2, -1);
l.resize(2);
r.resize(2);
int cur = 1;
stack<int> st;
st.push(1);
adj[1].push_back(1);
for (int i = 0; i < s.length(); i++) {
if (s[i] != 'm' && s[i] != '?') continue;
cur = st.top();
st.pop();
if (s[i] == 'm') {
if (s[i+1] == 'a') type[cur] = 1;
else type[cur] = 0;
adj.emplace_back();
adj[cur].push_back(adj.size()-1);
adj[adj.size()-1].push_back(cur);
adj.emplace_back();
adj[cur].push_back(adj.size()-1);
adj[adj.size()-1].push_back(cur);
st.push(adj.size()-1);
st.push(adj.size()-2);
l.emplace_back();
l.emplace_back();
r.emplace_back();
r.emplace_back();
type.push_back(-1);
type.push_back(-1);
i += 3;
}
else if (s[i] == '?') {
l[cur] = 1;
r[cur] = 1;
}
}
leaves.resize(adj.size());
dfs(1, 1);
cout << r[1]-l[1]+1 << '\n';
return 0;
}
