//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("Ofast")
/*#pragma GCC optimize("section-anchors")
#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
#pragma GCC optimize("vpt")
#pragma GCC optimize("rename-registers")
#pragma GCC optimize("move-loop-invariants")
#pragma GCC optimize("unswitch-loops")
#pragma GCC optimize("function-sections")
#pragma GCC optimize("data-sections")
#pragma GCC optimize("branch-target-load-optimize")
#pragma GCC optimize("branch-target-load-optimize2")
#pragma GCC optimize("btr-bb-exclusive")*/
//#pragma GCC optimize("inline")
//#pragma comment(linker, "/STACK:167077260")
#define _CRT_SECURE_NO_WARNINGS
#include <chrono>
#include <set>
#include <map>
#include <deque>
#include <string>
#include <cstdint>
#include <cmath>
#include <queue>
#include <cassert>
#include <random>
#include <bitset>
#include <iomanip>
#include <numeric>
#include <time.h>//////////////
#include <ctime>
#include <climits>
#include <string>
#include <cstdio>
#include <vector>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
//++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++
//#define endl '\n'
#define mp make_pair
#define pbc push_back
#define pob pop_back()
#define empb emplace_back
#define queuel queue<long long>
#define sqr(a) ((a) * (a))
#define lsqr(a) (ld(a) * a)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pin(p) cin >> p.first >> p.second;
#define uniq(a) sort(all(a));(a).resize(unique(all(a)) - a.begin());
#define rev(v) reverse(v.begin(), v.end());
#define sout(s, c) for (auto i : s) cout << i << c;
#define pout(p) cout << p.first << " " << p.second;
#define er(v, l, r) erase(v.begin() + l, v.begin() + r);
#define vin(v) for (ll i = 0; i < v.size(); ++i) cin >> v[i];
#define vout(v, c) for (int i = 0; i < v.size(); ++i) cout << v[i] << c;
#define pushi(v, a) for (int i = 0; i < a.size(); ++i) v.push_back(a[i]);
#define fastio() ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0); srand(time(NULL))
#define dab(v) for(auto i:v)cout<<i<<' ';
#define sp system("pause")
#define left left228
#define type type1337
#define right right228
//++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++
using namespace std;
//++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
//++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++
const ld EPS = 1e-5;
const ld EPS2 = 1e-12;
const ld PI = acos(-1);
int mod = (int)998244353;
const int MOD7 = 1000000007;
const int MOD9 = 1000000009;
const int a228 = 18;
const int inf = 1e9;
mt19937 rnd(time(0));
const ll kekmod = 1791791791;
const ll bestmod = 1148822869;
#define int ll
signed main()
{
	fastio();
	int n;
	cin >> n;
	map<pair<string, bool>, int> dist;
	vector<string> a(n);
	vector<int> c(n);
	for (int i = 0; i < n; ++i)
	{
		cin >> a[i] >> c[i];
	}
	set<pair<int, pair<string, bool>>> q;
	ll ans = 1e18;
	for (int i = 0; i < n; ++i)
	{

		ll nw = (dist.count({ a[i],0 }) ? dist[{a[i], 0}] : 1e18);
		dist[{a[i], 0}] = dist[{a[i], 1}] = min(nw, c[i]);
		q.insert({ c[i],{ a[i],0 } });
		q.insert({ c[i],{ a[i], 1 } });
		string ts = a[i];
		rev(ts);
		if (ts == a[i])
		{
			ans = min(ans, c[i]);
		}
	}
	while (q.size())
	{
		auto now = q.begin()->second;
		q.erase(q.begin());
		if (!now.first.size()) continue;
		for (int i = 0; i < n; ++i)
		{
			string tv = now.first, tu = a[i];
			if (now.second)
			{
				int ti = 0, tj = tv.size() - 1;
				bool f = 0;
				while (ti < tu.size() && tj >= 0)
				{
					if (tu[ti] != tv[tj])
					{
						f = 1;
						break;
					}
					++ti;
					--tj;
				}
				if (f) continue;
				string keks = "";
				bool nw = 0;
				if (ti == tu.size())
				{
					++tj;
					keks = string(tv.begin(), tv.begin() + tj);
					nw = 1;
				}
				else
				{
					keks = string(tu.begin() + ti, tu.end());
					nw = 0;
				}
				if (!dist.count({ keks,nw }) || dist[{keks, nw}] > dist[now] + c[i])
				{
					q.erase({ dist[{keks, nw}],{ keks,nw } });
					dist[{keks, nw}] = dist[now] + c[i];
					q.insert({ dist[{keks, nw}],{ keks, nw } });
				}
			}
			else
			{
				int ti = tu.size() - 1, tj = 0;
				bool f = 0;
				while (ti >= 0 && tj < tv.size())
				{
					if (tu[ti] != tv[tj])
					{
						f = 1;
						break;
					}
					ti--;
					tj++;
				}
				if (f) continue;
				string keks = "";
				bool nw = 0;
				if (ti == -1)
				{
					keks = string(tv.begin() + tj, tv.end());
					nw = 0;
				}
				else
				{
					++ti;
					keks = string(tu.begin(), tu.begin() + ti);
					nw = 1;
				}
				if (!dist.count({ keks,nw }) || dist[{keks, nw}] > dist[now] + c[i])
				{
					q.erase({ dist[{keks, nw}],{ keks,nw } });
					dist[{keks, nw}] = dist[now] + c[i];
					q.insert({ dist[{keks, nw}],{ keks, nw } });
				}
			}
		}
	}	
	for (auto i : dist)
	{
		string ts = i.first.first;
		rev(ts);
		if (ts == i.first.first)ans = min(ans, i.second);
	}
	if (ans > 1e17) cout << -1;
	else
		cout << ans;
	sp;
}

Measured memory_bytes: 3244