#include <iostream>
#include <algorithm>
using namespace std;
int main(void) {
	string s;
	cin >> s;
	auto res = find(s.begin(), s.end(), 'w');
	int pos = res - s.begin(),
		c = res - s.begin() - 1,
		w = s.end() - res;
	cout << min(c, w) << endl;
	return 0;
}