#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ull = unsigned long long;
const int INF = 0x3f3f3f3f;
const ll mod = 1e9 + 7;
const int N = 2e5 + 5;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);
    string s;
    cin >> s;
    int n = 0 , m = 0; // n - C  m - P
    for (int i = 0 ; i < s.size() ; i++)
    {
        if (s[i] == 'C') n++;
        if (s[i] == 'P') m++;
    }
    int ans = 0;
    if (n >= 3 && m >= 1)
    {
        ans++;
        n -= 3;
        m--;
        int p = min(n / 2 , m);
        ans += p;
    }
    cout << ans;
    return 0;
}