#include<bits/stdc++.h>
using namespace std;
int main(){
    string s;
    cin>>s;
    vector<int> c,w;
    for(int i=0;i<s.size();++i){
        if(s[i]=='c')c.emplace_back(i);
        if(s[i]=='w')w.emplace_back(i);
    }
    int ans=1e9;
    for(int i=0;i<c.size();++i){
        int tmp;
        for(int j=1;j<w.size();++j){
            if(c[i]<w[j-1]){
                ans=min(ans,w[j]-c[i]+1);
                break;
            }
        }
    }
    if(ans==1e9)ans=-1;
    cout<<ans<<endl;
}