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

int main() {
    string s;
    cin>>s;
    int cnt = 0;
    int start;
    int ans = 1e9;
    for (int i = 0; i < s.size(); i++) {
        if (cnt == 0 && s[i] == 'c') {
            cnt++;
            start = i;
        } else if (cnt == 1 && s[i] == 'w') cnt++;
        else if (cnt == 2 && s[i] == 'w') {
            cnt = 0;
            ans = min(ans, i-start+1);
        }
    }
    if (ans == 1e9) ans = -1;
    cout << ans << endl;
    return 0;
}