// >>> TEMPLATES
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define int ll
#define double ld
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define rep1(i,n) for (int i = 1; i <= (int)(n); i++)
#define repR(i,n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep1R(i,n) for (int i = (int)(n); i >= 1; i--)
#define loop(i,a,B) for (int i = a; i B; i++)
#define loopR(i,a,B) for (int i = a; i B; i--)
#define all(x) begin(x), end(x)
#define allR(x) rbegin(x), rend(x)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fst first
#define snd second
template <class Int> auto constexpr inf = numeric_limits<Int>::max()/2-1;
auto constexpr INF32 = inf<int32_t>;
auto constexpr INF64 = inf<int64_t>;
auto constexpr INF   = inf<int>;
#ifdef LOCAL
#include "debug.hpp"
#else
#define dump(...) (void)(0)
#define say(x) (void)(0)
#define debug if (0)
#endif
template <class T> using pque_max = priority_queue<T>;
template <class T> using pque_min = priority_queue<T, vector<T>, greater<T> >;
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
ostream& operator<<(ostream& os, T const& v) { bool f = true; for (auto const& x : v) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
istream& operator>>(istream& is, T &v) { for (auto& x : v) is >> x; return is; }
template <class T, class S> ostream& operator<<(ostream& os, pair<T,S> const& p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <class T, class S> istream& operator>>(istream& is, pair<T,S>& p) { return is >> p.first >> p.second; }
struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup;
template <class F> struct FixPoint : private F {
    constexpr FixPoint(F&& f) : F(forward<F>(f)) {}
    template <class... T> constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward<T>(x)...); }
};
struct MakeFixPoint {
    template <class F> constexpr auto operator|(F&& f) const { return FixPoint<F>(forward<F>(f)); }
};
#define MFP MakeFixPoint()|
#define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__)
template <class T, size_t d> struct vec_impl {
    using type = vector<typename vec_impl<T,d-1>::type>;
    template <class... U> static type make_v(size_t n, U&&... x) { return type(n, vec_impl<T,d-1>::make_v(forward<U>(x)...)); }
};
template <class T> struct vec_impl<T,0> { using type = T; static type make_v(T const& x = {}) { return x; } };
template <class T, size_t d = 1> using vec = typename vec_impl<T,d>::type;
template <class T, size_t d = 1, class... Args> auto make_v(Args&&... args) { return vec_impl<T,d>::make_v(forward<Args>(args)...); }
template <class T> void quit(T const& x) { cout << x << endl; exit(0); }
template <class T, class U> constexpr bool chmin(T& x, U const& y) { if (x > y) { x = y; return true; } return false; }
template <class T, class U> constexpr bool chmax(T& x, U const& y) { if (x < y) { x = y; return true; } return false; }
template <class It> constexpr auto sumof(It b, It e) {
    using S = typename iterator_traits<It>::value_type;
    using T = conditional_t<is_signed_v<S>,i64,u64>;
    return accumulate(b,e,T{});
}
template <class T> int sz(T const& x) { return x.size(); }
template <class C, class T> int lbd(C const& v, T const& x) {
    return lower_bound(v.begin(), v.end(), x)-v.begin();
}
template <class C, class T> int ubd(C const& v, T const& x) {
    return upper_bound(v.begin(), v.end(), x)-v.begin();
}
const int dx[] = { 1,0,-1,0 };
const int dy[] = { 0,1,0,-1 };
constexpr int popcnt(ll x) { return __builtin_popcountll(x); }
template <class Int> Int rand(Int a, Int b) { // [a,b]
    static mt19937_64 mt{random_device{}()};
    return uniform_int_distribution<Int>(a,b)(mt);
}
i64 irand(i64 a, i64 b) { return rand<i64>(a,b); }
u64 urand(u64 a, u64 b) { return rand<u64>(a,b); }
// <<<
// >>> BIT

struct BIT {
    int n;
    vector<int> v; // use v[1..n]
    BIT(int n = 0) : n(n), v(n+1) {}
    int size() const { return n; }
    int operator[](int i) const { return get(i); }
    int get(int i) const { return sum(i+1)-sum(i); }
    void set(int i, int x) { add(i,x-get(i)); }
    void add(int i, int x) {
        assert(0 <= i); assert(i < n);
        for (i++; i <= n; i += i&(-i)) v[i] += x;
    }
    int sum(int r) const { // [0,r)
        assert(0 <= r); assert(r <= n);
        int s = 0;
        for (int i = r; i > 0; i -= i&(-i)) s += v[i];
        return s;
    }
    int sum(int l, int r) const { // [l,r)
        return sum(r)-sum(l);
    }
    // lower_bound({sum(0),sum(1),...,sum(n)}, x)
    int lower_bound(int x) const {
        if (x <= 0) return 0;
        int s = 0, i = 0, w = 1;
        while (2*w <= n) w *= 2;
        for ( ; w; w >>= 1) {
            if (i+w <= n && s+v[i+w] < x) {
                s += v[i+w];
                i += w;
            }
        }
        return i+1;
    }
    int upper_bound(int x) const {
        int s = 0, i = 0, w = 1;
        while (2*w <= n) w *= 2;
        for ( ; w; w >>= 1) {
            if (i+w <= n && s+v[i+w] <= x) {
                s += v[i+w];
                i += w;
            }
        }
        return i+1;
    }
};

// <<<

int32_t main() {
    string s; cin >> s;
    const int n = s.size();

    vector<int> cnt(26), now(26);
    rep (i,n) cnt[s[i]-'a']++;

    vector<string> v(3);
    int ans = 0;
    for (char c : s) {
        c -= 'a';
        int x = -1;
        if (cnt[c]%2 == 0) {
            if (now[c] < cnt[c]/2) x = 0;
            else x = 2;
        } else {
            if (now[c] < cnt[c]/2) x = 0;
            else if (now[c] == cnt[c]/2) x = 1;
            else x = 2;
        }
        rep (y,3) if (y > x) ans += v[y].size();
        v[x] += c+'a';
        now[c]++;
    }
    if (sz(v[1]) > 1) quit(-1);

    auto S = v[0], T = v[2];
    reverse(all(T));
    assert(S.size() == T.size());
    const int m = S.size();

    vector<vector<int>> pos(26);
    rep (i,m) pos[S[i]-'a'].eb(i);

    vector<int> idx(T.size(),-1);
    repR (i,m) idx[i] = pos[T[i]-'a'].back(), pos[T[i]-'a'].pop_back();
    dump(idx);

    BIT bit(m);
    rep (i,m) ans += bit.sum(idx[i]+1,m), bit.add(idx[i],1);

    cout << ans << endl;

}


Measured memory_bytes: 6288