#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> oset;
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(), x.end()
#define IMAX INT_MAX
#define IMIN INT_MIN
#define LMAX LLONG_MAX
#define LMIN LLONG_MIN
#define MOD 1000000007
#define SIR 1000000009
int n = 0;
struct obj {
int type; // no, min, max
obj *l, *r;
int vl, vr;
obj() {
type = 0;
l = nullptr, r = nullptr;
vl = 0;
vr = 0;
};
void spracuj() {
if (type == 0) return;
if (type == 1) {
vl = min(l->vl, r->vl);
vr = l->vr + r->vr + 1;
} else {
vr = min(l->vr, r->vr);
vl = l->vl + r->vl + 1;
}
}
};
pair<obj*, int> read(string& s, int cur) {
obj* nw = new obj();
if (s[cur] == '?') return {nw, cur + 2};
auto tmp1 = read(s, cur + 4);
nw->l = tmp1.ff;
auto tmp2 = read(s, tmp1.ss);
nw->r = tmp2.ff;
if (s[cur + 1] == 'a') {
nw->type = 2;
} else {
nw->type = 1;
}
nw->spracuj();
return {nw, tmp2.ss + 1};
}
string pomoc = "?NX";
void out(obj* x) {
if (x->type == 0) {
cout << '?';
return;
}
cout << pomoc[x->type] << '(';
out(x->l);
cout << ',';
out(x->r);
cout << ')';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
string s;
cin >> s;
for (auto& c : s) n += (c == '?');
auto [root, koniec] = read(s, 0);
int mn = root->vl + 1;
int mx = n - root->vr;
cout << mx - mn + 1 << '\n';
return 0;
}
