#include<bits/stdc++.h>
#define int long long
using namespace std;
void solve(){
    string s;
    cin>>s;
    int cntc=0,cntp=0;
    for(int i=0;i<s.size();i++){
        if(s[i]=='C') cntc++;
        else if(s[i]=='P') cntp++;
    }
    cntc--;
    int ans=min(cntc/2,cntp);
    cout<<ans<<endl;
}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T=1;
    //cin>>T;
    while(T--){
        solve();
    }
    return 0;
}