#include <bits/stdc++.h>
using namespace std;
int main(){
    string s;
    cin>>s;
    transform(s.begin(), s.end(), s.begin(), ::tolower);
    string::size_type index1 = s.find_first_of('c');
    string::size_type index2 = s.find_first_of('w',index1);
    index2 = index2+1;
    string::size_type index3 = s.find_first_of('w',index2);
    index2 = index2-1;
    if(index1==string::npos||index2==string::npos||index3==string::npos){
        cout << -1 << endl;
        return 0;
    }
    int res = index3-index1+1;
    cout << (index1<index2&&index2<index3&&index1<index3?res:-1)<< endl;
    return 0;
}