#include <algorithm>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <vector>

const int MOD = 1e9 + 7;
const int iINF = 2147483647 / 2;
const long long int llINF = 9223372036854775807 / 2;

using namespace std;
using ll = long long int;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using vvvl = vector<vector<vector<ll>>>;

typedef pair<ll, ll> pll;
bool paircomp(const pll &a, const pll &b) {
  if (a.first == b.first)
    return a.second < b.second;
  return a.first < b.first;
}

#define REP(i, n) for (ll i = 0; i < (n); i++)
#define RREP(i, n) for (ll i = (n)-1; i >= 0; i--)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define AUTO(i, m) for (auto &i : m)
#define ALL(a) (a).begin(), (a).end()
#define MAX(vec) *std::max_element(vec.begin(), vec.end())
#define MIN(vec) *std::min_element(vec.begin(), vec.end())
#define ARGMAX(vec)                                                            \
  std::distance(vec.begin(), std::max_element(vec.begin(), vec.end()))
#define ARGMIN(vec)                                                            \
  std::distance(vec.begin(), std::min_element(vec.begin(), vec.end()))
#define REV(T) greater<T>()
#define PQ(T) priority_queue<T, vector<T>, greater<T>>
#define VVL(a, b, c) vector<vector<ll>>(a, vector<ll>(b, c))
#define VV(T, a, b, c) vector<vector<T>>(a, vector<T>(b, c))
#define VVVL(a, b, c, d)                                                       \
  vector<vector<vector<ll>>>(a, vector<vector<ll>>(b, vector<ll>(c, d)))
#define VVV(T, a, b, c, d)                                                     \
  vector<vector<vector<T>>>(a, vector<vector<T>>(b, vector<T>(c, d)))
#define SP(a) fixed << setprecision(a)
#define SQRT(a) sqrt((long double)(a))
#define DPOW(a, b) pow((long double)(a), (long double)(b))
#define UNIQUE(vec)                                                            \
  do {                                                                         \
    sort(ALL((vec)));                                                          \
    (vec).erase(std::unique(ALL((vec))), (vec).end());                         \
  } while (0)

ll POW(ll n, ll m) {
  if (m == 0) {
    return 1;
  } else if (m % 2 == 0) {
    ll tmp = POW(n, m / 2);
    return (tmp * tmp);
  } else {
    return (n * POW(n, m - 1));
  }
}

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

using Node = pair<string, int>; // left: 0, right: 1

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ll N;
  cin >> N;
  vector<string> S(N);
  vl C(N);
  REP(i, N) { cin >> S[i] >> C[i]; }

  ll res = llINF;
  map<Node, ll> dp;
  priority_queue<pair<ll, Node>, vector<pair<ll, Node>>,
                 greater<pair<ll, Node>>>
      que;

  auto func = [&](const string &left, const string &right) {
    ll i = left.size() - 1, j = 0;
    while (true) {
      if (i == -1 || j == right.size())
        break;
      if (left[i] != right[j])
        return Node("", -1);
      --i, ++j;
    }
    if (left.size() >= right.size()) {
      string res = left.substr(0, left.size() - right.size());
      return Node(res, 0);
    } else {
      string res = right.substr(left.size());
      return Node(res, 1);
    }
  };

  auto relax = [&](const string &left, const string &right, ll cost) {
    auto v = func(left, right);

    if (v.second == -1)
      return;
    if (v.first == "")
      res = min(cost, res);
    else {
      que.push(make_pair(cost, v));
      if (dp.count(v))
        dp[v] = min(dp[v], cost);
      else
        dp[v] = cost;
    }
  };

  REP(i, N) {
    REP(j, S[i].size() + 1) {
      string left = S[i].substr(0, j), right = S[i].substr(j);
      relax(left, right, C[i]);
    }
    REP(j, S[i].size()) {
      string left = S[i].substr(0, j), right = S[i].substr(j + 1);
      relax(left, right, C[i]);
    }
  }

  while (!que.empty()) {
    auto tmp = que.top();
    que.pop();
    ll dist = tmp.first;
    string cur = tmp.second.first;
    ll type = tmp.second.second;
    if (dist > dp[Node(cur, type)])
      continue;
    REP(i, N) {
      if (type == 0)
        relax(cur, S[i], dist + C[i]);
      else
        relax(S[i], cur, dist + C[i]);
    }
  }
  cout << (res < llINF ? res : -1) << endl;

  return 0;
}


Measured memory_bytes: 3844