#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

/*** O(N) ver. ***/

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define pb push_back
#define ALL(a) (a).begin(),(a).end()

int main() {
    string S;
    cin >> S;
    int N = S.length();
    int mx = N + 1;
    int w1 = N, w2 = N;
    RREP(i, N) {
        if (S[i] == 'w') {
            w2 = w1;
            w1 = i;
        }
        if (S[i] == 'c' && w2 != N) {
            mx = min(mx, w2 - i + 1);
        }
    }
    if (mx == N + 1) mx = -1;
    cout << mx << endl;
    return 0;
}