#include <iostream>
#include <string>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <unordered_map>
#include <map>
#include <set>
#include <algorithm>
#include <queue>
#include <stack>
#include <functional>
#include <bitset>
#include <assert.h>
#include <unordered_map>
#include <fstream>
#include <ctime>
#include <complex>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef pair<ll,ll> P;
typedef pair<int,int> pii;
typedef vector<P> vpl;
typedef tuple<ll,ll,ll> tapu;
#define rep(i,n) for(int i=0; i<(n); i++)
#define REP(i,a,b) for(int i=(a); i<(b); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const int inf = 1<<30;
const ll linf = 1LL<<62;
const int MAX = 510000;
ll dy[8] = {1,-1,0,0,1,-1,1,-1};
ll dx[8] = {0,0,1,-1,1,-1,-1,1};
const double pi = acos(-1);
const double eps = 1e-7;
template<typename T1,typename T2> inline bool chmin(T1 &a,T2 b){
	if(a>b){
		a = b; return true;
	}
	else return false;
}
template<typename T1,typename T2> inline bool chmax(T1 &a,T2 b){
	if(a<b){
		a = b; return true;
	}
	else return false;
}
template<typename T> inline void print(T &a){
    rep(i,a.size()) cout << a[i] << " ";
    cout << "\n";
}
template<typename T1,typename T2> inline void print2(T1 a, T2 b){cout << a << " " << b << "\n";}
template<typename T1,typename T2,typename T3> inline void print3(T1 a, T2 b, T3 c){
	cout << a << " " << b << " " << c << "\n";
}
ll pcount(ll x) {return __builtin_popcountll(x);}
const int mod = 1e9 + 7;
//const int mod = 998244353;

struct state{
	string s;
	ll cost;
	int d;
	bool operator< (const state &st) const {
		return cost > st.cost;
	}
};

map<pair<string,int>,ll> mp;

void ins(string s, ll c, int d){
	if(mp.find({s,d}) != mp.end()){
		chmin(mp[{s,d}], c);
	}else{
		mp[{s,d}] = c;
	}
}

int main(){
	int n; cin >> n;
	vl c(n);
	vs s(n);
	rep(i,2) mp[{"",i}] = linf;
	rep(i,n){
		cin >> s[i] >> c[i];
		int m = s[i].size();
		rep(j,m){
			string t = s[i].substr(0,j);
			string u = t; reverse(all(u));
			if(t == u){
				string v = s[i].substr(j,m-j);
				ins(v,c[i],0);
			}
		}
		rep(j,m){
			string t = s[i].substr(j,s[i].size()-j);
			string u = t; reverse(all(u));
			if(t == u){
				string v = s[i].substr(0,j);
				reverse(all(v));
				ins(v,c[i],1);
			}
		}
	}
	priority_queue<state> pq;
	auto push = [&](string s, ll c, int d){
		state st;
		st.s = s; st.cost = c; st.d = d;
		if(mp.find({s,d}) != mp.end()){
			if(mp[{s,d}] > c){
				mp[{s,d}] = c;
				pq.emplace(st);
			}
		}else{
			mp[{s,d}] = c;
			pq.emplace(st);
		}
	};
	for(auto i : mp){
		state st;
		st.s = i.first.first; st.cost = i.second;
		st.d = i.first.second;
		pq.emplace(st);
	}
	while(!pq.empty()){
		auto p = pq.top(); pq.pop();
		if(mp[{p.s,p.d}] < p.cost) continue;
		rep(i,n){
			if(p.d == 0){
				reverse(all(s[i]));
				int si = s[i].size(), sp = p.s.size();
				if(si < sp){
					string t = p.s.substr(0,si);
					if(t == s[i]){
						push(p.s.substr(si,sp-si), p.cost+c[i], p.d);
					}
				}else{
					string t = s[i].substr(0,sp);
					if(t == p.s){
						push(s[i].substr(sp,si-sp), p.cost+c[i], 1-p.d);
					}
				}
				reverse(all(s[i]));
			}else{
				int si = s[i].size(), sp = p.s.size();
				if(si < sp){
					string t = p.s.substr(0,si);
					if(t == s[i]){
						push(p.s.substr(si,sp-si), p.cost+c[i], p.d);
					}
				}else{
					string t = s[i].substr(0,sp);
					if(t == p.s){
						push(s[i].substr(sp,si-sp), p.cost+c[i], 1-p.d);
					}
				}
			}
		}
	}
	ll ans = min(mp[{"",0}], mp[{"",1}]);
	if(ans == linf) cout << -1 << endl;
	else cout << ans << "\n";
}

Measured memory_bytes: 3804