#include "bits/stdc++.h"

#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout << (p) << endl;
#define sP(p) cout << setprecision(15) << fixed << p << endl;
#define pi 3.1415926535
#define IINF 1e9
#define LINF 1e18
#define vi vector<int>
#define mp make_pair

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 0, 1, 0, -1 };
int dy[] = { -1, 0, 1, 0 };

unsigned long long sttoi(std::string str) {
	unsigned long long ret;
	std::stringstream ss; ss << str;
	ss >> ret;
	return ret;
}

ull gcd(ull a, ull b) {
	if (b > a)swap(a, b);
	if (b == 0) return a;
	return gcd(b, a%b);
}

void solve() {
	string s;
	cin >> s;
	bool c = false, w = false;
	int st = -1;
	rep(i, s.length()) {
		if (c == false && s[i] == 'c') {
			c = true;
			st = i;
		}
		if (c == true && s[i] == 'w') {
			if (w == false) {
				w = true;
			}
			else {
				P(i - st + 1);
				return;
			}
		}
	}
	P(-1);
}

int main() {
	solve();
	return 0;
}