#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vl = vector<ll>;
template<class T> using vc = vector<T>;
template<class T> using vvc = vector<vector<T>>;

#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define repr(i, n) for (ll i = (n)-1; i >= 0; i--)
#define repe(i, l, r) for (ll i = (l); i < (r); i++)
#define reper(i, l, r) for (ll i = (r)-1; i >= (l); i--)
#define repa(i,n) for (auto& i: n)

template<class T> inline bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> inline bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
void init() {cin.tie(0);ios::sync_with_stdio(false);cout << fixed << setprecision(15);}

#ifdef DEBUG
template <class T, class N> void verr(const T& a, const N& n) { rep(i, n) cerr << a[i] << " "; cerr << "\n" << flush; }
ll dbgt = 1; void err() { cerr << "passed " << dbgt++ << "\n" << flush; }
template<class H, class... T> void err(H&& h,T&&... t){ cerr<< h << (sizeof...(t)?" ":"\n") << flush; if(sizeof...(t)>0) err(forward<T>(t)...); }
#endif

const ll INF = 4e18;
const ld EPS = 1e-11;
const ld PI = acos(-1.0L);
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
//--------------------------------------------------------------------------------//
template <typename T>
struct dijkstra{
    using P = pair<T, ll>;
    const T inf = numeric_limits<T>::max();
    vector<vector<pair<ll,T>>> G;
    vector<ll> beforev;
    vector<T> dist;
    ll N, start;
    priority_queue<P, vector<P>, greater<P>> pq;

    dijkstra(ll n) : N(n) {
        G.resize(n), beforev.assign(n, -1), dist.assign(n, inf);
    }

    void add_edge(ll u, ll v, T cost){
        G[u].emplace_back(v, cost);
    }

    void init(ll s = 0){
        start = s;
        fill(beforev.begin(), beforev.end(), -1), fill(dist.begin(), dist.end(), inf);
        dist[start] = 0, pq.emplace(0, start);
        
        while(!pq.empty()){
            T c; ll from;
            tie(c, from) = pq.top(), pq.pop();
            if (dist[from] < c) continue;
            for(auto& e: G[from]){
                ll to; T cost;
                tie(to, cost) = e;
                if(dist[to]>dist[from]+cost){
                    dist[to] = dist[from] + cost;
                    beforev[to] = from;
                    pq.emplace(dist[to], to);
                }
            }
        }
    }

    vector<ll> get_route(ll goal){
        vector<ll> route;
        ll now = goal;
        while(now!=-1){
            route.emplace_back(now);
            now = beforev[now];
        }
        reverse(route.begin(), route.end());
        return route;
    }
};

string rev(string s) {
    reverse(all(s));
    return s;
}

int main() {
    init();
    ll N;
    cin >> N;
    vc<string> S(N), R(N);
    vl C(N);
    rep(i, N) cin >> S[i] >> C[i], R[i] = rev(S[i]);

    // 部分文字列にidを振り分ける
    ll id = 1;
    vvc<ll> Sid(N), Rid(N);     // 正順と逆順の文字列idを持つ
    vl StartId, PldId;          // 始点候補, 回文候補を持つ
    rep(_, 2) {
        rep(i, N) {
            rep(j, S[i].size() + 1) {
                // 回文は終点候補
                if (S[i].substr(0, j) == rev(S[i].substr(0, j))) PldId.eb(id);
                Sid[i].eb(id), id++;
            }
            // 完全な文字列は始点候補
            StartId.eb(id - 1);
        }

        swap(S, R), swap(Sid, Rid);
    }

    // 部分文字列を頂点として辺を張る
    dijkstra<ll> G(id);
    rep(_, 2) {
        rep(i, N) repe(sn, 1, S[i].size() + 1) rep(j, N) {
            string s = rev(S[i].substr(0, sn)), t = S[j];

            ll tn = t.size();
            ll len = min(sn, tn);
            // 先頭が一致しないならスキップ
            if (s.substr(0, len) != t.substr(0, len)) continue;

            // s側の文字列が残る場合
            if (sn >= tn) {
                G.add_edge(Sid[i][sn], Sid[i][sn - tn], C[j]);
            }
            // t側の文字列が残る場合
            else {
                G.add_edge(Sid[i][sn], Rid[j][tn - sn], C[j]);
            }
        }
        swap(S, R), swap(Sid, Rid);
    }

    // id:0から完全な文字列へ辺を張る
    rep(i, 2 * N) {
        G.add_edge(0, StartId[i], C[i % N]);
    }

    // ダイクストラ法でid:0から単一始点最短路を求める
    G.init();

    // 回文候補のコストの最小値を得る
    ll ans = INF;
    repa(goal, PldId) chmin(ans, G.dist[goal]);

    cout << (ans == INF ? -1 : ans) << endl;
}

Measured memory_bytes: 3788