#include <bits/stdc++.h>
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define endl '\n'
const int INF = (1 << 30);
using namespace std;
typedef long long int ll;

void solve(){
    string s;
    cin >> s;
    auto c = s.find('w');
    auto w = s.length() - c;
    cout << min(c-1, w) << endl;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    solve();
}