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

int main() {
    string s;
    cin >> s;
    vector<int> ans;
    for(int i = 0;i < s.length();i++){
        if(s[i] == 'c'){
            int tester = 1;
            bool flag = false;
            for(int j = i + 1;j < s.length();j++){
                tester++;
                if(!flag && s[j] == 'w'){
                flag = true;
                }
                else if(flag && s[j] == 'w'){
                    ans.push_back(tester);
                    break;
                }
            }
        }
    }
    sort(ans.begin(), ans.end());
    if(ans.size() == 0)cout << -1 << endl;
    else cout << ans[0] << endl;
    return 0;
}