#include <bits/stdc++.h>
using namespace std;
struct Vertex {
int type, l, r;
};
int root = -1;
vector<Vertex> vertices;
int N = 0;
int parse() {
char car, useless;
cin >> car;
if(car == '?') {
int id = vertices.size();
vertices.push_back({0, -1, -1});
N++;
return id;
}
cin >> car;
cin >> car;
cin >> useless;
int l = parse();
cin >> useless;
int r = parse();
cin >> useless;
int id = vertices.size();
if(car == 'x') {
vertices.push_back({1, l, r});
}
else {
vertices.push_back({-1, l, r});
}
return id;
}
struct Ans {
int lx_l, lx_g, gx_l, gx_g;
};
Ans dyn_ans[2000 * 1000];
Ans calcule_ans(int v) {
Ans a;
if(vertices[v].type == 0) {
a = {1, 0, 0, 1};
}
else {
Ans ans_l = calcule_ans(vertices[v].l);
Ans ans_r = calcule_ans(vertices[v].r);
if(vertices[v].type == 1) {
a = {
ans_l.lx_l + ans_r.lx_l,
ans_l.lx_g + ans_r.lx_g,
min(ans_l.gx_l, ans_r.gx_l),
min(ans_l.gx_g, ans_r.gx_g)
};
} else {
a = {
min(ans_l.lx_l, ans_r.lx_l),
min(ans_l.lx_g, ans_r.lx_g),
ans_l.gx_l + ans_r.gx_l,
ans_l.gx_g + ans_r.gx_g
};
}
}
return dyn_ans[v] = a;
}
/*void debug(int root) {
if(vertices[root].type == 0) {
cerr << "?";
return;
}
if(vertices[root].type == 1) cerr << "max";
else cerr << "min";
cerr << "{";
cerr << dyn_ans[root].lx_l << ",";
cerr << dyn_ans[root].lx_g << ",";
cerr << dyn_ans[root].gx_l << ",";
cerr << dyn_ans[root].gx_g;
cerr << "}";
cerr << "(";
debug(vertices[root].l);
cerr << ",";
debug(vertices[root].r);
cerr << ")";
}*/
vector<pair<int, int>> inters;
void gen_inters(int v, int a = 0, int b = 0) {
if(vertices[v].type == 0) {
inters.push_back({a, N - b});
}
else {
if(vertices[v].type == 1) {
gen_inters(
vertices[v].l,
a + dyn_ans[vertices[v].r].lx_l,
b + dyn_ans[vertices[v].r].lx_g
);
gen_inters(
vertices[v].r,
a + dyn_ans[vertices[v].l].lx_l,
b + dyn_ans[vertices[v].l].lx_g
);
} else {
gen_inters(
vertices[v].l,
a + dyn_ans[vertices[v].r].gx_l,
b + dyn_ans[vertices[v].r].gx_g
);
gen_inters(
vertices[v].r,
a + dyn_ans[vertices[v].l].gx_l,
b + dyn_ans[vertices[v].l].gx_g
);
}
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
root = parse();
calcule_ans(root);
gen_inters(root);
vector<int> vals(N + 1, 0);
for(pair<int, int> inter : inters) {
vals[inter.first]++;
vals[inter.second]--;
}
int sum = 0;
int nbPossibles = 0;
for(int i = 0;i < N;i++) {
sum += vals[i];
if(sum > 0) nbPossibles++;
}
cout << nbPossibles << endl;
return 0;
}
