#pragma GCC optimize ("O3")
#pragma GCC target ("avx")

#include <bits/stdc++.h>

using namespace std;


using int64 = long long;
const int mod = (1e9 + 7);

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


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

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}


int main() {
  int N;
  cin >> N;
  vector< string > S(N);
  vector< int > C(N);
  for(int i = 0; i < N; i++) {
    cin >> S[i] >> C[i];
  }
  auto pre_dp = make_v< int64 >(N, 20); // ....abcd    ....
  auto suf_dp = make_v< int64 >(N, 20); // .....   abc.....
  fill_v(pre_dp, infll);
  fill_v(suf_dp, infll);
  int64 ret = infll;
  using T = tuple< int64, int, int, int >;
  priority_queue< T, vector< T >, greater<> > que;
  for(int i = 0; i < N; i++) {
    pre_dp[i][0] = C[i];
    que.emplace(C[i], 0, i, 0);
    suf_dp[i][S[i].size() - 1] = C[i];
    que.emplace(C[i], 1, i, S[i].size() - 1);
  }
  while(!que.empty()) {
    int64 cost;
    int type, idx, pos;
    tie(cost, type, idx, pos) = que.top();
    que.pop();
    if(type == 0) {
      int rest = (int) S[idx].size() - pos;


      string X = S[idx].substr(pos, rest);
      string Y{X};
      reverse(begin(Y), end(Y));
      if(X == Y) {
        chmin(ret, cost);
      }

      for(int i = 0; i < N; i++) {
        bool match = true;
        if(S[i].size() == rest) {
          for(int j = 0; j < rest; j++) {
            match &= S[idx][pos + j] == S[i][(int) S[i].size() - 1 - j];
          }
          if(match) chmin(ret, cost + C[i]);
        } else if(S[i].size() > rest) {
          for(int j = 0; j < rest; j++) {
            match &= S[idx][pos + j] == S[i][(int) S[i].size() - 1 - j];
          }
          if(match && chmin(suf_dp[i][(int) S[i].size() - 1 - rest], cost + C[i])) {
            que.emplace(cost + C[i], 1, i, (int) S[i].size() - 1 - rest);
          }
        } else {
          for(int j = 0; j < S[i].size(); j++) {
            match &= S[idx][pos + j] == S[i][(int) S[i].size() - 1 - j];
          }
          if(match && chmin(pre_dp[idx][pos + S[i].size()], cost + C[i])) {
            que.emplace(cost + C[i], 0, idx, pos + S[i].size());
          }
        }
      }
    } else {
      int rest = pos + 1;


      string X = S[idx].substr(0, rest);
      string Y{X};
      reverse(begin(Y), end(Y));
      if(X == Y) {
        chmin(ret, cost);
      }

      for(int i = 0; i < N; i++) {
        bool match = true;
        if(S[i].size() == rest) {
          for(int j = 0; j < rest; j++) {
            match &= S[idx][pos - j] == S[i][j];
          }
          if(match) chmin(ret, cost + C[i]);
        } else if(S[i].size() > rest) {
          for(int j = 0; j < rest; j++) {
            match &= S[idx][pos - j] == S[i][j];
          }
          if(match && chmin(pre_dp[i][rest], cost + C[i])) {
            que.emplace(cost + C[i], 0, i, rest);
          }
        } else {
          for(int j = 0; j < S[i].size(); j++) {
            match &= S[idx][pos - j] == S[i][j];
          }
          if(match && chmin(suf_dp[idx][pos - S[i].size()], cost + C[i])) {
            que.emplace(cost + C[i], 1, idx, pos - S[i].size());
          }
        }
      }

    }
  }

  if(ret >= infll) ret = -1;
  cout << ret << "\n";
}



Measured memory_bytes: 3696