#include<bits/stdc++.h>
using namespace std;

//#define int long long

typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>void chmax(T &t,U f){if(t<f)t=f;}

char c[]="cww*";

signed main(){
    string s;cin>>s;
    int ans=101;
    rep(i,s.size())reps(j,1,s.size()-i+1){
        string ss=s.substr(i,j);
        int t=0;
        rep(k,ss.size())if(ss[k]==c[t])t++;
        if(t==3)chmin(ans,j);
    }
    if(ans==101)cout<<-1<<endl;
    else cout<<ans<<endl;
    return 0;
}