#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

struct edge { ll to, d; };
vector<vector<edge>> adj;

vector<ll> dijkstra(int n=0) {
  int N = adj.size();
  auto c = [](const p_ll &x, const p_ll &y){return x.second>y.second;};
  priority_queue<p_ll, vector<p_ll>, decltype(c)> q(c);
  vector<ll> result(N,LLINF); result[n] = 0; q.push(make_pair(n,0));
  while(q.size()) {
    p_ll now = q.top(); q.pop();
    ll np = now.first, nd = now.second;
    if (nd>result[np]) continue;
    for (auto x: adj[np]) {
      if (result[x.to]<=result[np]+x.d) continue;
      q.push(make_pair(x.to, result[np]+x.d));
      result[x.to] = result[np]+x.d;
    }
  }
  return result;
}

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

int main() {
  ll N; cin >> N;
  string S[N]; ll C[N]; rep(i,N) cin >> S[i] >> C[i];
  string RS[N]; rep(i,N) { RS[i] = S[i]; reverse(all(RS[i])); }
  map<string, ll> pre; rep(i,N) rep(j,S[i].size()) pre[RS[i].substr(j)]++;
  map<string, ll> suf; rep(i,N) rep(j,S[i].size()) suf[ S[i].substr(j)]++;

  ll idx = 1;
  for (auto &x: pre) { x.second = idx; idx++; }
  for (auto &x: suf) { x.second = idx; idx++; }
  idx++;
  // for (auto x: pre) cout << x.first << "->" << x.second << " "; cout << endl;
  // for (auto x: suf) cout << x.first << "->" << x.second << " "; cout << endl;

  string dict[idx] = {};
  for (auto x: pre) dict[x.second] = x.first;
  for (auto x: suf) dict[x.second] = x.first;
  // debug(dict,dict+idx);

  ll s_suf = suf.size(), s_pre = pre.size();
  adj.resize(idx);
  rep(i,N) {
    ll fpre = 0, tpre = pre[RS[i]];
    ll fsuf = 0, tsuf = suf[ S[i]];
    adj[fpre].push_back({tpre,C[i]});
    adj[fsuf].push_back({tsuf,C[i]});

    repr(j,1,s_pre+1) {
      if (dict[j].size()>S[i].size()) {
        if (dict[j].substr(0,S[i].size())==S[i]) {
          string left = dict[j].substr(S[i].size());
          adj[j].push_back({pre[left] ,C[i]});
          // cout << S[i] << "--" << dict[j] << endl;
        }
      }
      else if (dict[j].size()<S[i].size()) {
        if (S[i].substr(0,dict[j].size())==dict[j]) {
          string left = S[i].substr(dict[j].size());
          adj[j].push_back({suf[left] ,C[i]});
          // cout << S[i] << "----" << dict[j] << endl;
        }
      }
      else {
        if (S[i]==dict[j]) {
          adj[j].push_back({idx-1, C[i]});
          // cout << S[i] << "==" << dict[j] << endl;
        }
      }
    }

    repr(j,s_pre+1,s_suf+s_pre+1) {
      if (dict[j].size()>RS[i].size()) {
        if (dict[j].substr(0,RS[i].size())==RS[i]) {
          string left = dict[j].substr(RS[i].size());
          adj[j].push_back({suf[left] ,C[i]});
          // cout << S[i] << "--" << dict[j] << endl;
        }
      }
      else if (dict[j].size()<RS[i].size()) {
        if (RS[i].substr(0,dict[j].size())==dict[j]) {
          string left = RS[i].substr(dict[j].size());
          adj[j].push_back({pre[left] ,C[i]});
          // cout << S[i] << "----" << dict[j] << endl;
        }
      }
      else {
        if (RS[i]==dict[j]) {
          adj[j].push_back({idx-1, C[i]});
          // cout << S[i] << "==" << dict[j] << endl;
        }
      }
    }
  }

  vector<ll> d = dijkstra();
  // debug(all(d));
  // rep(i,idx) cout << dict[i] << "->" << d[i] << endl;

  ll result = LLINF;
  repr(i,1,idx) {
    string td = dict[i]; reverse(all(td));
    if (dict[i]==td) result = min(result,d[i]);
  }

  if (result==LLINF) result = -1;
  cout << result << endl;
  return 0;
}

Measured memory_bytes: 3916