#include<iostream>
#include<vector>
using namespace std;
int main() {
	string s;cin>>s;
	vector<int> c,w;
	for(int i=0;i<s.size();i++)
	{
		if(s[i]=='c')c.push_back(i);
		else if(s[i]=='w')w.push_back(i);
	}
	int m=10000;
	for(int i=0;i<c.size();i++)
	{
		int f=c[i];
		int cou=0;
		for(int j=0;j<w.size();j++)
		{
			if(f>w[j])continue;
			cou++;
			if(cou>=2)m=min(m,w[j]-f+1);
		}
	}
	if(m!=10000)cout<<m<<endl;
	else cout<<-1<<endl;
	return 0;
}