#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>
#include <cassert>


using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<n;++i)
#define FOR(i, a, b) for(int i=a;i<b;++i)
#define RREP(i, n) for(int i=n-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=b-1;i>=a;--i)

#define all(x) begin(x),end(x)
#define dump(x) cerr<<#x<<" = "<<(x)<<endl
#define debug(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}


template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> p) {
    os << p.first << ":" << p.second;
    return os;
}

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

template<class T1, class T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
    os << "[";
    for (auto it = mp.begin(); it != mp.end(); ++it) {
        if (it != mp.begin()) {
            os << ", ";
        }
        os << *it;
    }
    return os << "]";
}

// edit

void solve() {
    int N;
    cin >> N;
    vector<string> S(N);
    vector<string> T(N);
    vector<ll> C(N);
    REP(i, N) cin >> S[i] >> C[i];
    REP(i, N) T[i] = S[i];
    REP(i, N) reverse(all(T[i]));
    ll ans = LINF;
    for (int i = 0; i < N; ++i) {
        if (T[i] == S[i]) {
            chmin(ans, C[i]);
        }
    }

    using Node = pair<int, string>;

    map<Node, ll> dist;
    priority_queue<pair<ll, Node>, vector<pair<ll, Node>>, greater<>> pq;
    for (int i = 0; i < N; ++i) {
        Node node = make_pair(1ll, S[i]);
        if (!dist.count(node)) {
            dist[node] = LINF;
        }
//        chmin(dist[node], C[i]);
        if (dist[node] > C[i]) {
            dist[node] = C[i];
            pq.emplace(C[i], node);
        }
    }

    while (!pq.empty()) {
        auto top = pq.top();
        pq.pop();
        int sig = top.second.first;
        auto suf = top.second.second;
        for (int i = 0; i < N; ++i) {
            if (sig == -1) {
                ll next_cost = top.first + C[i];
                int len = min(S[i].size(), suf.size());
                if (S[i].substr(0, len) == suf.substr(0, len)) {
                    string next_str;
                    int next_sig;
                    if (S[i] == suf) {
                        if (dist.count(Node(0, ""))) {
                            if (dist[Node(0, "")] > next_cost) {
                                dist[Node(0, "")] = next_cost;
                            }
                        } else {
                            dist[Node(0, "")] = next_cost;
                        }
                        continue;
                    }
                    if (S[i].size() > suf.size()) {
                        next_str = S[i].substr(suf.size());
                        next_sig = 1;
                    } else {
                        next_str = suf.substr(S[i].size());
                        next_sig = -1;
                    }

                    string R = next_str;
                    reverse(all(R));
                    if (R == next_str) {
                        if (dist.count(Node(0, ""))) {
                            if (dist[Node(0, "")] > next_cost) {
                                dist[Node(0, "")] = next_cost;
                            }
                        } else {
                            dist[Node(0, "")] = next_cost;
                        }
                        continue;
                    }

                    Node next_node = make_pair(next_sig, next_str);
                    if (dist.count(next_node) == 0) {
                        dist[next_node] = next_cost;
                        pq.emplace(next_cost, next_node);
                    } else {
                        if (dist[next_node] > next_cost) {
                            dist[next_node] = next_cost;
                            pq.emplace(next_cost, next_node);
                        }
                    }
                }
            } else {
                ll next_cost = top.first + C[i];
                int len = min(T[i].size(), suf.size());
                if (T[i].substr(0, len) == suf.substr(0, len)) {
                    if (T[i] == suf) {
                        if (dist.count(Node(0, ""))) {
                            if (dist[Node(0, "")] > next_cost) {
                                dist[Node(0, "")] = next_cost;
                            }
                        } else {
                            dist[Node(0, "")] = next_cost;
                        }
                        continue;
                    }
                    string next_str;
                    int next_sig;
                    if (T[i].size() > suf.size()) {
                        next_str = T[i].substr(suf.size());
                        next_sig = -1;
                    } else {
                        next_str = suf.substr(T[i].size());
                        next_sig = 1;
                    }

                    string R = next_str;
                    reverse(all(R));
                    if (R == next_str) {
                        if (dist.count(Node(0, ""))) {
                            if (dist[Node(0, "")] > next_cost) {
                                dist[Node(0, "")] = next_cost;
                            }
                        } else {
                            dist[Node(0, "")] = next_cost;
                        }
                        continue;
                    }

                    Node next_node = make_pair(next_sig, next_str);
                    if (dist.count(next_node) == 0) {
                        dist[next_node] = next_cost;
                        pq.emplace(next_cost, next_node);
                    } else {
                        if (dist[next_node] > next_cost) {
                            dist[next_node] = next_cost;
                            pq.emplace(next_cost, next_node);
                        }
                    }
                }
            }
        }
    }

    if (dist.count(Node(0, ""))) {
        ll tmp = dist[Node(0, "")];
//        assert(tmp % 2 == 0);

        chmin(ans, tmp);
        cout << ans << endl;
    } else {
        cout << -1 << endl;
    }


}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
//    std::ifstream in("input.txt");
//    std::cin.rdbuf(in.rdbuf());

    solve();


    return 0;
}


Measured memory_bytes: 3264