#include <bits/stdc++.h>
#include "hiccup.h"
//~ #include "grader.cpp"
using namespace std;
const int N = 1000001;
int n;
string s;
vector <int> h;
set <int> v[N], g[N];
bool valid(){
int o = 0;
for(auto &i : s){
o += i == 'H';
o -= i == 'C';
if(o < 0) return 0;
}
if(o) return 0;
for(auto &i : s){
if(i == 'H') o = 0;
else if(i == 'C') o = 1;
else if(o == 0) return 0;
}
return 1;
}
bool check(int x){
for(int i = 0 ; ; i++){
if((int)v[i].size() == 0) break;
g[i] = v[i];
}
for(int i = n - 1 ; i >= 0 ; i--){
if(s[i] == 'C'){
for(int j = 0 ; j < x ; j++){
auto it = g[h[i]].upper_bound(i);
if(it == g[h[i]].end()) return 0;
g[h[i]].erase(it);
}
}
}
return 1;
}
int HicCup(std::string S) {
s = S;
n = s.size();
if(!valid() || s == string(n, '!')) return -1;
h.resize(n);
h[0] = 1;
for(int i = 1 ; i < n ; i++){
h[i] = h[i - 1];
if(s[i] == 'H') h[i]++;
else if(s[i] == 'C') h[i]--;
else v[h[i]].insert(i);
}
int l = 0, r = n;
while(l <= r){
int mid = (l + r) / 2;
if(check(mid)) l = mid + 1;
else r = mid - 1;
}
return l - 1;
}
