#include <bits/stdc++.h>

using namespace std;

#define int long long
#define fi first
#define se second
#define endl '\n'

typedef pair<int,int> PII;

void solve(){
	string s;
	cin >>s;
	map<char,int> mp;
	for(int i = 0;i < s.size();i ++){
		mp[s[i]] ++;
	}
	cout<<min(mp['P'],mp['C'] / 3);
}

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int T;
	T = 1;
	while(T --){
		solve();
	}
}