#include <bits/stdc++.h>
using namespace std;
#define int long long
#define stoi stoll
using pii=pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
#define all(c) begin(c),end(c)
#define rall(c) rbegin(c),rend(c)
#define fore(x,c) for(auto &&x:c)
#define rep(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define rrep(i, a, n) for(int i=(int)(n-1);i>=a;--i)
#define sz(c) ((int)c.size())
#define contains(c,x) (c.find(x)!=end(c))
#define inseg(l,x,r) ((l)<=(x)&&(x)<(r))
#define dump(...)
#define pb push_back
#define _ 0
const signed INF_=1001001001; const long long INF=1001001001001001001LL;
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) os<<*i<<(i==end(v)-1?"":" ");return os;}
template<class T> istream& operator>>(istream &is,vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) is>>*i;return is;}
template<class T,class U> istream& operator>>(istream &is, pair<T,U> &p) {
    is>>p.first>>p.second;return is;}
template<class T, class U> bool chmax(T &a,const U &b){return a<b?a=b,1:0;}
template<class T, class U> bool chmin(T &a,const U &b){return a>b?a=b,1:0;}
template <class T> void psum(T& c) {partial_sum(begin(c), end(c), begin(c));}
template<class T> using heap=priority_queue<T,vector<T>,greater<T>>;
struct before_main_function {
    before_main_function() {
        cin.tie(nullptr); ios::sync_with_stdio(0);
        cout << setprecision(15) << fixed;
        // #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

// 1-indexed
struct BIT {
    int size;
    int pow2_less;
    vector<int> data;
    BIT(int n): size(n + 1), data(n + 1, 0) {
        pow2_less = 1;
        while ((pow2_less << 1) <= size)
            pow2_less <<= 1;
    }
    void add(int i, int x) {
        while (i < size) {
            data[i] += x;
            i += i & -i;
        }
    }
    int sum(int i) {
        int ret = 0;
        while (i > 0) {
            ret += data[i];
            i -= i & -i;
        }
        return ret;
    }
    // sum(x) >= w となる最小のxを返す
    int lower_bound(int w) {
        if (w <= 0) return 0;
        int x = 0;
        for (int k = pow2_less; k > 0; k >>= 1) {
            if (x + k < size && data[x + k] < w) {
                w -= data[x + k];
                x += k;
            }
        }
        return x + 1;
    }
};

int calc(vi p) {
    int N = sz(p);
    BIT bit(N);
    int ret = 0;
    rrep(i, 0, N) {
        ret += bit.sum(p[i]);
        bit.add(p[i], 1);
    }
    return ret;
}

signed main() {
    string S;
    cin >> S;
    map<int, int> cnt1, cnt2;
    int N = sz(S);
    rep(i, 0, N) cnt1[S[i]]++;
    vector<int> kind(N);

    map<int, stack<int>> st;
    int x = 0, y = 0, z = 0;
    rep(i, 0, N) {
        if (cnt1[S[i]] == cnt2[S[i]] * 2 + 1) {
            kind[i] = 1;
            y++;
        } else if (cnt1[S[i]] > cnt2[S[i]] * 2) {
            kind[i] = 0;
            x++;
        } else {
            kind[i] = 2;
            st[S[i]].push(i);
            z++;
        }
        cnt2[S[i]]++;
    }
    dump(x, y, z);
    if (y > 1 || x != z) {
        cout << -1 << endl;
        return 0;
    }

    vi num(3);
    vi p;
    string tmp;
    rep(i, 0, N) {
        int idx = 0;
        if (kind[i] == 0) idx = num[kind[i]], tmp += S[i];
        if (kind[i] == 1) idx = num[kind[i]] + x;
        if (kind[i] == 2) idx = num[kind[i]] + x + y;
        p.push_back(idx + 1);
        num[kind[i]]++;
    }
    rep(i, 0, sz(tmp)) {
        int t = st[tmp[i]].top(); st[tmp[i]].pop();
        p[t] = N - i;
    }

    dump(p);
    int ans = calc(p);
    cout << ans << endl;
    return (0^_^0);
}



Measured memory_bytes: 7816