#define _USE_MATH_DEFINES
#include<bits/stdc++.h>
using namespace std;

#define int long long

string S;

signed main()
{
	cin >> S;
	int ans = 101;
	for (int i = 0; i < S.size(); i++)
	{
		if (S[i] != 'c') continue;
		int cnt = 0;
		for (int j = 0; j < 2; j++)
		{
			while (i < S.size() && S[i] != 'w') cnt++, i++;
			if (i >= S.size()) goto NEXT;
			cnt++; i++;
		}
		ans = min(cnt, ans);
NEXT:;
	}
	if (ans > 100) puts("-1");
	else printf("%lld\n", ans);
	return 0;
}