#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);

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