#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define o(a) cout << a << endl
#define int long long
#define first first
#define second se
using namespace std;
typedef pair<int, int> P;
typedef vector<int> vi;

signed main(){
    string s;
    cin >> s;
    int c, w;
    rep(i, 0, s.size()){
        if(s[i] == 'w'){
            c = i;
            break;
        }
    }
    w = s.size() - c;
    int ans = min(c - 1, w);
    o(ans);
}