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

#define int long long

string S;

signed main()
{
	cin >> S;
	int f = 0, ans = 1, p = 0;
	while (f < S.size() && S[f++] != 'c') ;
	for (int i = f; i < S.size(); i++)
	{
		ans++;
		if (S[i] == 'w')
		{
			if (++p >= 2) break;
		}
	}
	if (p < 2) puts("-1");
	else printf("%lld\n", ans);
	return 0;
}