#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void solve(){
    string s;
    cin>>s;
    vector<int> p(26);
    for(auto i:s){
        p[i-'A']++;
    }
    if(p[2]==0){
        cout<<"0\n";
        return; 
    }
    p[2]--;
    if(p['P'-'A']*2>=p[2]){
        cout<<p[2]/2<<'\n';
    }
    else{
        cout<<p['P'-'A']<<'\n';
    }
    
}
int main() {
    ios::sync_with_stdio(0),cin.tie(0);
    int _ = 1;
    // cin>>_;
    while(_--)  solve();
 
}