#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 w1, w2, ans = 100;

int main()
{
	in >> S;

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

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