#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)

int main() {
    string s;
    cin >> s;
    vector<int> c, w;
    REP(i, s.length()) {
        if (s[i] == 'c') c.push_back(i);
        if (s[i] == 'w') w.push_back(i);
    }
    int ans = INT_MAX;
    REP(i, int(c.size())) {
        REP(j, int(w.size()) - 1) {
            if (w[j] > c[i]) {
                ans = min(ans, w[j + 1] - c[i] + 1);
                break;
            }
        }
    }
    cout << ((ans == INT_MAX) ? -1 : ans) << endl;
    return 0;
}