//{{{
#include <bits/stdc++.h>
using namespace std;
#define rep(...) repN((__VA_ARGS__,rep3,rep2,loop,~))(__VA_ARGS__)
#define loop(n) rep2(_loop_,n)
#define rep2(i,n) rep3(i,0,n)
#define rep3(i,begin,end) for(int i=(int)(begin),i##_end=(int)(end);i<i##_end;++i)
#define repN(a) repX a
#define repX(a0,a1,a2,x,...) x
//}}}

int f(const char *s){
	int count = 0;
	int res = 0;
	while(*s != 0){
		res++;
		if(*s == 'w') count++;
		if(count == 2) return res;
		s++;
	}
	return -1;
}

int main(void){
	string S;
	cin >> S;

	int ans = 1000;
	rep(i, S.size()){
		if(S[i] == 'c'){
			int res = f(&S.c_str()[i]);
			if(res != -1 && res < ans){
				ans = res;
			}
		}
	}
	if(ans == 1000) ans = -1;
	cout << ans << endl;
	return 0;
}