#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
#define dump(x)                             \
    if (dbg) {                              \
        cerr << #x << " = " << (x) << endl; \
    }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
namespace mydef {
const int INF = 1ll << 60;
const int MOD = 1e9 + 7;
template <class T>
bool chmin(T& a, const T& b) {
    if (a > b) {
        a = b;
        return 1;
    } else
        return 0;
}
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    } else
        return 0;
}
void Yes(bool flag = true) {
    if (flag)
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
}
void No(bool flag = true) {
    Yes(!flag);
}
void YES(bool flag = true) {
    if (flag)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
}
void NO(bool flag = true) {
    YES(!flag);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T& val) {
    std::fill((T*)array, (T*)(array + N), val);
}
bool dbg = false;
}  // namespace mydef
using namespace mydef;
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vp vector<pair<int, int>>
#define vvp vector<vector<pair<int, int>>>
#define pi pair<int, int>
//#define P pair<int, int>
//#define V vector<int>
//#define S set<int>
#define asn ans

int N;
string S[100];
int C[100];
using P = pair<pair<string, int>, int>;

bool pan(string S) {
    string s = S;
    reverse(all(s));
    return S == s;
}

void solve() {
    int ans = INF;
    for (int i = 0; i < N; i++) {
        string s = S[i];
        reverse(all(s));
        if (S[i] == s)
            chmin(ans, C[i]);
    }
    auto compare = [](P x, P y) { return x.second > y.second; };
    priority_queue<P, vector<P>, decltype(compare)> que{compare};
    for (int i = 0; i < N; i++) {
        que.push(make_pair(make_pair(S[i], 1ll), C[i]));
    }
    int cnt = 0;
    clock_t start = clock();
    while (!que.empty()) {
        cnt++;
        /*
        if (cnt >= 1e5) {
            cout << -1 << endl;
            exit(0);
        }
        */
        if (cnt % 100 == 0) {
            clock_t end = clock();
            double time = static_cast<double>(end - start) / CLOCKS_PER_SEC;
            if (time > 1.9) {
                cout << -1 << endl;
                exit(0);
            }
        }
        auto p = que.top();
        que.pop();
        string s = p.first.first;
        int parity = p.first.second;
        int cost = p.second;
        if (cost >= ans)
            continue;
        for (int i = 0; i < N; i++) {
            auto nc = C[i];
            if (cost + nc >= ans)
                continue;
            auto ns = S[i];
            string s = p.first.first;
            if (parity == 1) {
                while (s.size() > 0 && ns.size() > 0) {
                    if (s.front() == ns.back()) {
                        s.erase(s.begin());
                        ns.pop_back();
                    } else
                        break;
                }
                if (s.size() == 0) {
                    if (pan(ns)) {
                        chmin(ans, cost + nc);
                    } else
                        que.push(make_pair(make_pair(ns, 0), cost + nc));
                } else if (ns.size() == 0) {
                    if (pan(s)) {
                        chmin(ans, cost + nc);
                    } else
                        que.push(make_pair(make_pair(s, 1), cost + nc));
                }
            } else {
                while (s.size() > 0 && ns.size() > 0) {
                    if (ns.front() == s.back()) {
                        ns.erase(ns.begin());
                        s.pop_back();
                    } else
                        break;
                }
                if (s.size() == 0) {
                    if (pan(ns)) {
                        chmin(ans, cost + nc);
                    } else
                        que.push(make_pair(make_pair(ns, 1), cost + nc));
                } else if (ns.size() == 0) {
                    if (pan(s)) {
                        chmin(ans, cost + nc);
                    } else
                        que.push(make_pair(make_pair(s, 0), cost + nc));
                }
            }
        }
    }
    if (ans == INF) {
        ans = -1;
    }
    cout << ans << endl;
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> S[i] >> C[i];
    }

    solve();
    return 0;
}


Measured memory_bytes: 3764