#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 c = false, w = false;

int main()
{
	in >> S;

	rep(i, S.length())
	{
		if (c && w && S[i] == 'w')
		{
			ans = std::min(ans, i - seek + 1);
			c = w = false;
		}
		if (S[i] == 'c')
		{
			c = true;
			seek = i;
		}
		if (S[i] == 'w' && c) { w = true; }
	}
	ans = ((ans == 100) ? (-1) : (ans));

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