#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

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