#include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(a);i>=(b);i--)
#define pb push_back

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef set<int> si;
const int inf = 1e9;
const int mod = 1e9+7;

string s;
int c, cw;
main(){
  cin.tie(0);
  ios::sync_with_stdio(false);


  cin >> s;
  int ans = inf;
  c = cw = (-1)*inf;
  FOR(i, 0, s.size()){
    switch(s[i]){
      case 'c':
        c = i;
        break;
      case 'w':
        ans = min(ans, i - cw + 1);
        cw = c;
        break;
      default:
        break;
    }
  }
  if(ans >= inf) ans = -1;
  cout << ans << endl;
}