#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

int main()
{
    const string cww = "cww";

    string s;
    cin >> s;
    int n = s.size();

    int ans = INT_MAX;
    for(int i=0; i<n; ++i){
        int j = i;
        for(int k=0; k<3; ++k){
            j = s.find(cww[k], j);
            if(j == string::npos)
                break;
            ++ j;
        }

        if(j != string::npos)
            ans = min(ans, j - i);
    }

    if(ans == INT_MAX)
        cout << -1 << endl;
    else
        cout << ans << endl;

    return 0;
}