// Author: Chuanhua Yu
// Time: 2024-11-26.
#include<bits/stdc++.h>
using namespace std;
using ll = long long;



void solve(){
    string s;
    cin >> s;
    int c0 = 0, c1 = 0;
    for(auto c : s) {
        c0 += (c == 'C');
        c1 += (c == 'P');
    }
    int ans = c1;
    if(c0 < c1 * 2 + 1) ans = (c0 - 1) / 2;
    cout << ans << '\n';
}

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