#include <bits/stdc++.h>
 
using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
// #define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#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 rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(int)(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
// vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
const ll MOD = 1000000007;
// const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'

vector<vll> dp(55, vll(22, vl(2, INF)));

signed main() {
    fio();

    int n;
    cin >> n;
    vector<string> s(n);
    vl c(n);
    rep (i, n) cin >> s[i] >> c[i];

    using P = pair<ll, pair<pii, int>>;
    priority_queue<P, vector<P>, greater<P>> pq;
    ll ans = INF;
    rep (i, n) {
        rep (j, s[i].size()) {
            int j1 = j - 1, j2 = j + 1;
            bool flag = true;
            while (j1 >= 0 and j2 < s[i].size()) {
                if (s[i][j1] == s[i][j2]) {
                    j1--;
                    j2++;
                }
                else {
                    flag = false;
                    break;
                }
            }
            if (flag) {
                if (j1 == -1 and j2 == s[i].size()) {
                    chmin(ans, c[i]);
                }
                else {
                    if (j1 == -1) {
                        if (dp[i][j2][1] > c[i]) {
                            dp[i][j2][1] = c[i];
                            pq.push(P(c[i], {pii(i, j2), 1}));
                        }
                    }
                    else {
                        if (dp[i][j1][0] > c[i]) {
                            dp[i][j1][0] = c[i];
                            pq.push(P(c[i], {pii(i, j1), 0}));
                        }
                    }
                }
            }
        }

        for (int j = -1; j < (int)s[i].size(); j++) {
            int j1 = j, j2 = j + 1;
            bool flag = true;
            while (j1 >= 0 and j2 < (int)s[i].size()) {
                if (s[i][j1] == s[i][j2]) {
                    j1--;
                    j2++;
                }
                else {
                    flag = false;
                    break;
                }
            }
            if (flag) {
                if (j1 == -1 and j2 == s[i].size()) {
                    chmin(ans, c[i]);
                }
                else {
                    if (j1 == -1) {
                        if (dp[i][j2][1] > c[i]) {
                            dp[i][j2][1] = c[i];
                            pq.push(P(c[i], {pii(i, j2), 1}));
                        }
                    }
                    else {
                        if (dp[i][j1][0] > c[i]) {
                            dp[i][j1][0] = c[i];
                            pq.push(P(c[i], {pii(i, j1), 0}));
                        }
                    }
                }
            }
        }
    }
    // 1: ????abc
    // 0: abc????

    while (pq.size()) {
        P temp = pq.top();
        pq.pop();
        ll score = temp.first;
        int i = temp.second.first.first, j = temp.second.first.second, k = temp.second.second;
        //DEBUG(score);
        //DEBUG(make_pair(pii(i, j), k));
        //DEBUG(dp[i][j][k]);
        if (dp[i][j][k] < score) continue;

        rep (ni, n) {
            if (k == 0) {
                string t = s[ni];
                int jj;
                bool flag = true;
                for (jj = j; jj >= 0; jj--) {
                    if (j - jj >= (int)(int)t.size()) break;
                    // //DEBUG(pii(i, ni));
                    // //DEBUG(jj);
                    // //DEBUG(j - jj);
                    if (s[i][jj] != t[j - jj]) {
                        flag = false;
                        break;
                    }
                }

                if (flag) {
                    if (jj == -1) {
                        if (j - jj == (int)(int)t.size()) {
                            chmin(ans, score + c[ni]);
                        }
                        else {
                            if (dp[ni][j - jj][1] > score + c[ni]) {
                                //DEBUG("aaa");
                                dp[ni][j - jj][1] = score + c[ni];
                                pq.push(P(score + c[ni], {pii(ni, j - jj), 1}));
                            }
                        }
                    }
                    else {
                        if (dp[i][jj][0] > score + c[ni]) {
                            //DEBUG("bbb");
                            dp[i][jj][0] = score + c[ni];
                            pq.push(P(score + c[ni], {pii(i, jj), 0}));
                        }
                    }
                }
            }
            else {
                string t = s[ni];
                int jj;
                bool flag = true;
                for (jj = j; jj < s[i].size(); jj++) {
                    if ((int)(int)(int)t.size() - 1 - (jj - j) < 0) break;
                    if (s[i][jj] != t[(int)t.size() - 1 - (jj - j)]) {
                        flag = false;
                        break;
                    }
                }
                // //DEBUG(jj);
                // //DEBUG(ni);
                // //DEBUG(flag);

                if (flag) {
                    if (jj == s[i].size()) {
                        if ((int)(int)(int)t.size() - 1 - (jj - j) < 0) {
                            chmin(ans, score + c[ni]);
                        }
                        else {
                            if (dp[ni][(int)(int)t.size() - 1 - (jj - j)][0] > score + c[ni]) {
                                // //DEBUG("ccc");
                                dp[ni][(int)(int)t.size() - 1 - (jj - j)][0] = score + c[ni];
                                pq.push(P(score + c[ni], {pii(ni, (int)(int)t.size() - 1 - (jj - j)), 0}));
                            }
                        }
                    }
                    else {
                        if (dp[i][jj][1] > score + c[ni]) {
                            // ////DEBUG("ddd");
                            dp[i][jj][1] = score + c[ni];
                            pq.push(P(score + c[ni], {pii(i, jj), 1}));
                        }
                    }
                }
            }
        }
    }
    if (ans == INF) {
        cout << -1 << endl;
    }
    else {
        cout << ans << endl;
    }
}


Measured memory_bytes: 3732