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

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