#include <iostream>
using namespace std;

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