#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(n); i++)
using namespace std;
typedef long long ll;

int main(){
	string s; cin>>s;
	
	regex re(R"(c\w*?w\w*?w)");
	smatch match{};
	
	if(regex_search(s, re)==false){
		cout << "-1" << endl;
		return 0;
	}
	
  vector<int> v;
	while(regex_search(s, match, re)){
		string r=match[0];
		int w=r.size();
		v.push_back(w);
		s = match.suffix();
	}
  sort(v.begin(), v.end());
	cout << v[0] << endl;
}