#include <algorithm>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
typedef long long int ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define rep(i,x) for(int i=0;i<(int)(x);++i)
#define reps(i,x) for(int i=1;i<=(int)(x);++i)
#define rrep(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define pb push_back

string s;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> s;
    int n = s.size();
    int w1 = n, w2 = n, ret = n + 1;
    rrep(i, s.size()) {
        if (s[i] == 'w') {
            w2 = w1;
            w1 = i;
        } else if (s[i] == 'c' && w2 != n) {
            ret = min(ret, w2 - i + 1);
        }
    }
    cout << (ret > n ? -1 : ret) << "\n";
    return 0;
}