//#include <bits/stdc++.h>
//#pragma GCC optimize(2)
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<cmath>
#include<cstring>
#include<bitset>
#include<stack>
#include<time.h>



#define X first
#define Y second
#define PB push_back
#define MP make_pair
#define scd(a) scanf("%d",&a)
#define scdd(a,b) scanf("%d%d",&a,&b)
#define scddd(a,b,c) scanf("%d%d%d",&a,&b,&c)
#define ALL(x) x.begin(),x.end()
#define sz(a) ((int)a.size())
#define getmid ((l+r)>>1)
#define mst(var,val) memset(var,val,sizeof(var))
#define IOS ios::sync_with_stdio(false);cin.tie(0)
#define lowbit(x) x&(-x)
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
#define ls rt<<1
#define rs rt<<1|1
using namespace std;
#ifdef local
#define dbg(args...) cout << #args << " -> ", err(args);
void err(){ cout << endl; }
template<typename T, typename... Args>
void err(T a, Args... args){ cout << a << ' '; err(args...); }
#else
#define dbg(args...)
#endif // local

typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
typedef pair <ll, int> pli;
typedef pair <double, double> pdd;
const int inf=0x3f3f3f3f;
const long long INF=0x3f3f3f3f3f3f3f3fLL;
const double PI=acos(-1.0);
const long double eps=1e-8;
const int mod=998244353;
const int maxn=3e5+100;
const int N=1e5+100;
const int M=500+10;
const ll mm=(1LL<<32);

template <class T>
inline void read(T &x)
{
    x = 0;
    char c = getchar();
    bool f = 0;
    for (; !isdigit(c); c = getchar())
        f ^= c == '-';
    for (; isdigit(c); c = getchar())
        x = x * 10 + (c ^ 48);
    x = f ? -x : x;
}

template <class T>
inline void write(T x)
{
    if (x < 0)
    {
        putchar('-');
        x = -x;
    }
    T y = 1;
    int len = 1;
    for (; y <= x / 10; y *= 10)
        ++len;
    for (; len; --len, x %= y, y /= 10)
        putchar(x / y + 48);
}
ll qpow(ll a,ll b,ll mod)
{
    ll ans=1;
    while(b)
    {
        if(b&1)
            ans=(ans*a)%mod;
        b>>=1;
        a=(a*a)%mod;
    }
    return ans;
}


vector<pll>g[N];
struct node{
    int u;ll d;
    bool operator<(const node&b)const{
        return d>b.d;
    }
};
int n;
ll dis[N],c[100];
int id[100][50],idx;
void dij()
{
    priority_queue<node>q;
    for(int i=0;i<=idx+5;++i) dis[i]=INF;
    for(int i=0;i<n;++i)
    {
        dis[id[i][0]]=c[i];
        q.push({id[i][0],c[i]});
    }
    while(!q.empty())
    {
        node tmp=q.top();q.pop();
        int u=tmp.u;ll d=tmp.d;
        if(d>dis[u]) continue;
        for(auto e:g[u])
        {
            int v=e.X;ll val=e.Y;
            if(dis[v]>dis[u]+val)
            {
                dis[v]=dis[u]+val;
                q.push({v,dis[v]});
            }
        }
    }
}
string s[200];
string rev(string s)
{
    reverse(s.begin(),s.end());
    return s;
}
int main()
{
#ifdef local
    freopen("in.txt","r",stdin);
#endif // local
    IOS;cout.tie(0);
    cin>>n;
    for(int i=0;i<n;++i)
    {
        cin>>s[i]>>c[i];
        s[i+n]=rev(s[i]);
        c[i+n]=c[i];
    }
    idx=1;int T=0;
    for(int i=0;i<2*n;++i)
    {
        int l=s[i].size();
        for(int j=0;j<l;++j) id[i][j]=++idx;
    }
    for(int i1=0;i1<2*n;++i1)
    {
        int l1=s[i1].size();
        for(int j=0;j<l1;++j)
        {
            int u=id[i1][j];
            for(int i2=0;i2<2*n;++i2)
            {
                if(i1/n==i2/n) continue;//看是不是同一堆
                int l2=s[i2].size();
                int w=min(l2,l1-j);
                if(s[i1].substr(j,w)!=s[i2].substr(0,w)) continue;
                int v;
                if(l2>w) v=id[i2][w];
                else if(l1-j>w) v=id[i1][j+w];
                else v=T;
                g[u].push_back(pll(v,c[i2]));
            }
        }
    }
    dij();
    ll ans=dis[T];
    for(int i=0;i<2*n;++i)
    {
        int l=s[i].size();
        for(int j=0;j<l;++j)
        {
            string t=s[i].substr(j);
            if(t==rev(t)) ans=min(ans,dis[id[i][j]]);
        }
    }
    if(ans==INF) ans=-1;
    cout<<ans<<endl;
    return 0;
}


Measured memory_bytes: 6064