#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define SZ(n) (int)(n).size()
#define ALL(n) (n).begin(), (n).end()
#define MOD % 1000000007
using namespace std;
typedef long long LL;
typedef vector<int> VI;

int main() {
	string s;
	cin >> s;
	int ans = 0;
	REP(i, SZ(s)) {
		if (s[i] == 'w') {
			ans = i;
			break;
		}
	}
	if (SZ(s) / 2 >= ans) {
		cout << ans - 1 << endl;
	}
	else {
		cout << SZ(s) - ans << endl;
	}
	return 0;
}