#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ff first
#define ss second
ll ttt;
const ll INF=1e18;
const ll MOD=1e9+7;
const ll N=2000007;
ll n,m,k;
int tp[N];
int l[N],r[N];
int x[N],y[N];
int sz[N];
int cur=1;
int ind=0;
vector<int>g[N];
string s;
int parse(){
int v=cur;
cur++;
char c=s[ind];
ind++;
if(c=='?'){
tp[v]=0;
return v;
}
c=s[ind];
ind+=3;
if(c=='i'){
tp[v]=1;
}
else{
tp[v]=2;
}
int lft=parse();
ind++;
int rgh=parse();
l[v]=lft;
r[v]=rgh;
ind++;
return v;
}
void recurs(int v){
if(tp[v]==0){
x[v]=y[v]=1;
sz[v]=1;
return;
}
recurs(l[v]);
recurs(r[v]);
sz[v]=sz[l[v]]+sz[r[v]];
if(tp[v]==1){
x[v]=min(x[l[v]],x[r[v]]);
y[v]=y[l[v]]+y[r[v]]-1;
}
else{
x[v]=x[l[v]]+x[r[v]];
y[v]=max(y[l[v]]+sz[r[v]],y[r[v]]+sz[l[v]]);
}
// cout<<v<<": "<<x[v]<<" "<<y[v]<<endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
// freopen("Binput.txt","r",stdin);
// freopen("Boutput.txt","w",stdout);
cin>>s;
int root=parse();
recurs(root);
cout<<y[root]-x[root]+1<<endl;
}
