#include "bits/stdc++.h"
using namespace std;

int main() {
	string S;
	cin >> S;
	int bC = -1, ans = 1000;
	bool C = false, W = false;
	for (int i = 0; i < S.size(); i++) {
		if (!C && S[i] == 'c') {
			bC = i;
			C = true;
		}
		if (C && !W && S[i] == 'w') {
			W = true;
		}
		else if (C && W && S[i] == 'w') {
			ans = min(ans, i - bC + 1);
			i = bC;
			C = false;
			W = false;
		}
	}
	if (ans == 1000) ans = -1;
	cout << ans << endl;
}