#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <valarray>
#include <vector>

#define N 1000
#define re(i,n) for(int i=0;i<(n);i++)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define fe(i,n,f) for_each(i,n,f)
#define bw(a,b,c) (((a)<=(b))&&((b)<=(c)))
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

int main(void){
	string s;
	int n=0;
	int m=999;
	int state=0;
	cin>>s;

	re(i,s.size()){
		switch (state) {
			case 0:
				if(s[i]=='c'){state=1;n=1;}
				break;
			case 1:
				n++;
				if(s[i]=='w')state=2;
				break;
			case 2:
				n++;
				if(s[i]=='w'){
					state=0;
					m=min(m,n);
				}
				break;
		}
	}
	for(int i=s.size()-1;i>=0;i--){
		switch (state) {
			case 0:
				if(s[i]=='w'){state=1;n=1;}
				break;
			case 1:
				n++;
				if(s[i]=='w')state=2;
				break;
			case 2:
				n++;
				if(s[i]=='c'){
					state=0;
					m=min(m,n);
				}
				break;
		}
	}


	cout<<(m!=999?m:-1)<<endl;
	return 0;
}