#include <queue>
#include <algorithm>
#include <vector>
#include <set>
#include <iostream>
#include <numeric>
#include <tuple>
#include <cmath>
using namespace std;
typedef long long int ll;
typedef pair<int, int> pii;
typedef tuple<ll, ll, ll> tiii;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define ALL(container) (container).begin(), (container).end()

int main(){
    string s;
    cin >> s;
    vector<int> wPos;
    int INF = 10000000;
    int minLength = INF;
    for(int i = (int)s.length()-1;i >= 0;i--)
    {
        if(s[i] == 'c')
        {
            if(wPos.size() >= 2)
            {
                minLength = min(minLength, wPos[wPos.size()-2] - i + 1);
            }
        }
        else if(s[i] == 'w')
        {
            wPos.push_back(i);
        }
    }
    if(minLength == INF)
    {
        cout << -1 << endl;
        return 0;
    }
    cout << minLength << endl;
    return 0;
}