#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	string s; cin >> s;
	int n = s.size();
	int ans = INF;
	rep(i, 0, n) {
		if (s[i] != 'w')continue;
		int c = -1, w = -1;
		rrep(j, 0, i)
			if (s[j] == 'c') {
				c = j;
				break;
			}
		rep(j, i + 1, n) {
			if (s[j] == 'w') {
				w = j;
				break;
			}
		}
		if (c == -1 || w == -1)continue;
		chmin(ans, w - c + 1);
	}
	cout << (ans == INF ? -1 : ans) << endl;
	return 0;
}