#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)

int main()
{
	string s; cin >> s;

	int phase = 0;
	int ans;
	rep(i, 0, s.length())
	{
		if (phase == 0 && s[i] == 'c')
		{
			phase++;
			ans = i;
		}
		else if (phase == 1 && s[i] == 'w')
			phase++;
		else if (phase == 2 && s[i] == 'w')
		{
			phase++;
			ans = i - ans + 1;
		}
	}

	if (phase == 3)
		cout << ans << endl;
	else
		cout << -1 << endl;
}