#include<bits/stdc++.h>
using namespace std;
#define int long long
using ULL = unsigned long long;
using LLL = __int128;
using PII = pair<int, int>;
const int inf = 0x3f3f3f3f;


void solve() {
    string s;
    cin >> s;
    int num1 = 0, num2 = 0;
    for (int i = 0; i < s.size(); ++ i) {
        if (s[i] == 'C') {
            num1 ++;
        }
        if (s[i] == 'P') {
            num2 ++;
        }
    }
    if (num1 == 0 || num2 == 0) {
        cout << 0 << '\n';
    } else {
        cout << min((num1 - 1) / 2, num2) << '\n';
    }
}

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