#include <iostream>
#include <string>
using namespace std;

int main(){
    int pos_c = 0;
    string cww = "cww";
    string s; cin >> s;

    if(s.length() < 3){
        cout << -1 << endl;
        return 0;
    }
    
    for(int i=0, j=0; i < s.length(); i++){
        if(s[i] == cww[j]){
            j++;
            if(1 == j)
                pos_c = i;
                
            if(3 == j){
                cout << i - pos_c + 1 << endl;
                return 0;
            }
        }
    }
    cout << -1 << endl;
    return 0;
}