#include<bits/stdc++.h>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

int main() {
    string S; cin >> S;
    int N = S.size();
    int ans = N + 1;
    rep(i, N) rep(j, i) rep(k, j)
        if (S[i] == 'w') if (S[j] == 'w') if (S[k] == 'c')
            ans = min(ans, i - k + 1);
    if (ans == N + 1) cout << "-1" << endl;
    else cout << ans << endl;
    return 0;
}