#include<bits/stdc++.h>
//ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//clock_t start=clock();clock_t end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int,int> pii;
typedef pair<pii,int> ppii;
typedef pair<int,pii> pipi;
typedef pair<ll,ll> pll;
typedef pair<pll,ll> ppll;
typedef pair<ll,pll> plpl;
typedef pair<pii,pii> pippi;
typedef tuple<ll,ll,ll> tl;
typedef pair<double,double> pdd;
typedef vector<vector<ll>> mat;
ll mod=1000000007;
ll mod2=998244353;
ll mod3=1000003;
ll mod4=998244853;
ll mod5=1000000009;
ll inf=1LL<<61;
int iinf=1<<30;
double pi=3.14159265358979323846;
double pi2=pi/2.0;
double eps=1e-8;
#define rep(i,m,n) for(ll i=m;i<n;i++)
#define rrep(i,n,m) for(ll i=n;i>=m;i--)
#define srep(itr,st) for(auto itr=st.begin();itr!=st.end();itr++)
#define mrep(itr,mp) for(auto& itr:mp)
#define Max(a,b) a=max(a,b)
#define Min(a,b) a=min(a,b)
//#define endl "\n"
int dh[4]={1,0,-1,0};
int dw[4]={0,1,0,-1};
int ddh[8]={-1,-1,-1,0,0,1,1,1};
int ddw[8]={-1,0,1,-1,1,-1,0,1};
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};
#define umh unordered_map<int,int,custom_hash>
ll gcd(ll a,ll b){
    if(a<0)a=-a;
    if(b<0)b=-b;
    if(a<b)swap(a,b);
    if(b==0)return a;
    if(a%b==0)return b;
    return gcd(b,a%b);
}
ll lcm(ll a,ll b){
    ll c=gcd(a,b);
    return a*b/c;
}
ll Pow(ll n,ll k){
    if(k<0)return 0;
    ll ret=1;
    ll now=n;
    while(k>0){
        if(k&1)ret*=now;
        now*=now;
        k/=2;
    }
    return ret;
}
ll beki(ll n,ll k,ll md){
  ll ret=1;
  ll now=n;
    now%=md;
  while(k>0){
    if(k%2==1){
      ret*=now;
      ret%=md;
    }
    now*=now;
    now%=md;
    k/=2;
  }
  return ret;
}
ll gyaku(ll n,ll md){
  return beki(n,md-2,md);
}
ll popcount(ll n){
    ll ret=0;
    ll u=n;
    while(u>0){
        ret+=u%2;
        u/=2;
        
    }
    return ret;
}


int main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll n;cin>>n;
    string s[n];ll c[n];
    rep(i,0,n)cin>>s[i]>>c[i];
    map<pair<string,int>,ll> mp;
    rep(i,0,n){
        rep(j,0,s[i].size()+1){
            string a=s[i].substr(0,j);
            string b=s[i].substr(j);
            int x=min(a.size(),b.size());
            reverse(a.begin(),a.end());
            if(a.substr(0,x)==b.substr(0,x)){
                if(a.size()>b.size()){
                    string d=a.substr(x);
                    reverse(d.begin(),d.end());
                    if(mp.count({d,0})==0)mp[{d,0}]=c[i];
                    else mp[{d,0}]=min(mp[{d,0}],c[i]);
                }
                else{
                    string d=b.substr(x);
                    if(mp.count({d,1})==0)mp[{d,1}]=c[i];
                    else mp[{d,1}]=min(mp[{d,1}],c[i]);
                }
            }
            if(j==s[i].size())break;
            a=s[i].substr(0,j);
            b.erase(b.begin());
            x=min(a.size(),b.size());
            reverse(a.begin(),a.end());
            if(a.substr(0,x)==b.substr(0,x)){
                if(a.size()>b.size()){
                    string d=a.substr(x);
                    reverse(d.begin(),d.end());
                    if(mp.count({d,0})==0)mp[{d,0}]=c[i];
                    else mp[{d,0}]=min(mp[{d,0}],c[i]);
                }
                else{
                    string d=b.substr(x);
                    if(mp.count({d,1})==0)mp[{d,1}]=c[i];
                    else mp[{d,1}]=min(mp[{d,1}],c[i]);
                }
            }
        }
    }
    typedef pair<ll,pair<string,int>> P;
    priority_queue<P,vector<P>,greater<P>> q;
    mrep(p,mp){
        q.push({p.second,p.first});
    }
    while(q.size()>0){
        P p=q.top();q.pop();
        string now=p.second.first;int ty=p.second.second;
        ll dis=p.first;
        if(mp[{now,ty}]<dis)continue;
        if(now==""){
            cout<<dis<<endl;
            return 0;
        }
        if(ty==0){
            rep(i,0,n){
                string a=now;
                string b=s[i];
                reverse(a.begin(),a.end());
                int x=min(b.size(),a.size());
                if(a.substr(0,x)==b.substr(0,x)){
                    if(a.size()>b.size()){
                        string d=a.substr(x);
                        reverse(d.begin(),d.end());
                        if(mp.count({d,0})==0){
                            mp[{d,0}]=c[i]+dis;
                            q.push({c[i]+dis,{d,0}});
                        }
                        else if(mp[{d,0}]>dis+c[i]){
                            mp[{d,0}]=c[i]+dis;
                            q.push({c[i]+dis,{d,0}});
                        }
                    }
                    else{
                        string d=b.substr(x);
                        if(mp.count({d,1})==0){
                            mp[{d,1}]=c[i]+dis;
                            q.push({c[i]+dis,{d,1}});
                        }
                        else if(mp[{d,1}]>dis+c[i]){
                            mp[{d,1}]=c[i]+dis;
                            q.push({c[i]+dis,{d,1}});
                        }
                    }
                }
            }
        }
        else{
            rep(i,0,n){
                string a=s[i];
                string b=now;
                reverse(a.begin(),a.end());
                int x=min(b.size(),a.size());
                if(a.substr(0,x)==b.substr(0,x)){
                    if(a.size()>b.size()){
                        string d=a.substr(x);
                        reverse(d.begin(),d.end());
                        if(mp.count({d,0})==0){
                            mp[{d,0}]=c[i]+dis;
                            q.push({c[i]+dis,{d,0}});
                        }
                        else if(mp[{d,0}]>dis+c[i]){
                            mp[{d,0}]=c[i]+dis;
                            q.push({c[i]+dis,{d,0}});
                        }
                    }
                    else{
                        string d=b.substr(x);
                        if(mp.count({d,1})==0){
                            mp[{d,1}]=c[i]+dis;
                            q.push({c[i]+dis,{d,1}});
                        }
                        else if(mp[{d,1}]>dis+c[i]){
                            mp[{d,1}]=c[i]+dis;
                            q.push({c[i]+dis,{d,1}});
                        }
                    }
                }
            }
        }
    }
    cout<<-1<<endl;
}



Measured memory_bytes: 3732