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

int main() {
    string str;
    cin >> str;
    const int inf = 1 << 28;
    int ans = inf;
    for (int i = 0; i < str.size() - 2; i++) {
        int j = i;
        while (j < str.size() && str[j] != 'c')j++; j++;
        while (j < str.size() && str[j] != 'w')j++; j++;
        while (j < str.size() && str[j] != 'w')j++;
        if (j < str.size()) ans = min(ans, j - i + 1);
    }

    if (ans < inf) cout << ans << endl;
    else cout << -1 << endl;

    return 0;
}