#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(0);
#define ll long long
using namespace std;

int ruch(string s)
{
    ll n = s.length();

    ll count = 0;

    for (int i = 0; i <n / 2; i++) {
        ll left = i, right = n - left - 1;
        while (left <right) {
            if (s[left] == s[right]) {
                break;
            }
            else {
                right--;
            }
        }if (left == right) {
            return -1;
        }
        for (int j = right; j <n - left - 1; j++) {
            swap(s[j], s[j + 1]);
            count++;
        }
    }
    return count;
}

int main()
{
    string s;
    cin>>s;
    if(s.size()==1){
        cout<<-1;
        return 0;
    }
    int ans1 = ruch(s);
    reverse(s.begin(), s.end());
    int ans2 = ruch(s);
 
    cout <<max(ans1, ans2);
 
    return 0;
}