#include "hiccup.h"
#include<bits/stdc++.h>
//using namespace std;
int HicCup(std::string S) {
int N = S.size();
if ( S[0] != 'H' ) return -1;
int up = N+3, down = 0;
while( down + 1 < up ) {
int cur = (up + down)/2;
std::stack<int> boo;
//std::cout<<up<<" "<<down<<std::endl;
for ( int i = 0 ; i < N ; ++i ) {
//push next
if ( S[i] == 'H' ) {
boo.push(-2);
} else if ( S[i] == 'C' ) {
boo.push(-1);
} else {
if ( boo.empty() || boo.top() < 0 ) { //h or c is current
boo.push(1);
} else {
int temp = boo.top();
boo.pop();
boo.push(temp+1);
}
}
//pop if possible
while( boo.size() > 2 ){
int c = boo.top();
boo.pop();
int b = boo.top();
boo.pop();
int a = boo.top();
boo.pop();
if ( a == -2 && b == -1 && c >= cur ) {
c -= cur;
if ( c ) {
if ( boo.empty() || boo.top() < 0 ) {
boo.push(c);
} else {
int temp = boo.top();
boo.pop();
boo.push(temp+c);
}
}
} else {
boo.push(a);
boo.push(b);
boo.push(c);
break;
}
}
}
if ( boo.empty() || (boo.size() == 1 && boo.top() >= 0) ) {
down = cur;
} else {
up = cur;
}
}
if ( down ) {
return down;
} else {
bool done = true;
int soo = 0;
for ( int i = 0 ; i < N ; ++i ) {
if ( S[i] == 'H' ) ++soo;
if ( S[i] == 'C' ) --soo;
if ( soo < 0 ) done = false;
}
if ( soo ) done = false;
if ( done ) return 0;
else return -1;
}
}
