#include "bits/stdc++.h"
#define MOD 1000000007
#define INF 11234567890
#define in std::cin
#define out std::cout
#define rep(i,N) for(int i=0;i<N;++i)
typedef long long int LL;

std::string S;
int seek, ans = 100;
bool w1 = false, w2 = false;

int main()
{
	in >> S;

	for (int i = S.length() - 1; i >= 0; --i)
	{
		if (S[i] == 'w' && !w2)
		{
			w2 = true;
			seek = i;
		}
		else if (S[i] == 'w' && !w1) { w1 = true; }
		if (S[i] == 'c' && w1 && w2)
		{
			ans = std::min(ans, seek - i + 1);
			w1 = false;
		}
	}
	ans = ((ans == 100) ? (-1) : (ans));

	out << ans << std::endl;
	return 0;
}