#include<bits/stdc++.h>
using namespace std;

int main(){
	string s; cin>>s;
	int c=0;
	while(c<s.size()&&s.at(c)!='c')++c;
	int w2=s.size()-1;
	while(w2>=0&&s.at(w2)!='w')--w2;
	int w1=w2-1;
	while(w1>=0&&s.at(w1)!='w')--w1;
	cout<<(c<w1&&w1<w2?w2-c+1:-1)<<"\n"s;
}