#include<bits/stdc++.h>
using namespace std;


#define li          long long int
#define rep(i,to)   for(li i=0;i<((li)(to));i++)
#define repp(i,start,to)    for(li i=(li)(start);i<((li)(to));i++)
#define pb          push_back
#define sz(v)       ((li)(v).size())
#define bgn(v)      ((v).begin())
#define eend(v)     ((v).end())
#define allof(v)    (v).begin(), (v).end()
#define dodp(v,n)       memset(v,(li)n,sizeof(v))
#define bit(n)      (1ll<<(li)(n))
#define mp(a,b)     make_pair(a,b)
#define rin rep(i,n)
#define EPS 1e-12
#define ETOL 1e-8
#define MOD 1000000007
typedef pair<li, li> PI;

#define INF bit(60)

#define DBGP 1


#define idp if(DBGP)
#define F first
#define S second
#define p2(a,b)     idp cout<<a<<"\t"<<b<<endl
#define p3(a,b,c)       idp cout<<a<<"\t"<<b<<"\t"<<c<<endl
#define p4(a,b,c,d)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<endl
#define p5(a,b,c,d,e)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<endl
#define p6(a,b,c,d,e,f)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<endl
#define p7(a,b,c,d,e,f,g)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<endl
#define p8(a,b,c,d,e,f,g,h)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<endl
#define p9(a,b,c,d,e,f,g,h,i)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<endl
#define p10(a,b,c,d,e,f,g,h,i,j)        idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<"\t"<<j<<endl
#define foreach(it,v)   for(__typeof((v).begin()) it=(v).begin(); it!=(v).end(); ++it)
#define p2p(x)      idp p2((x).F, (x).S)
#define dump(x,n)   idp{rep(i,n){cout<<x[i]<<" ";}puts("");}
#define dump2(x,n)  idp{rep(i,n){cout<<"["<<x[i].F<<" , "<<x[i].S<<"] ";}puts("");}
#define dumpi(x)    idp{foreach(it, x){cout<<(*it)<<" ";}puts("");}
#define dumpi2(x)   idp{foreach(it, x){cout<<"["<<(it)->F<<" , "<<(it)->S<<"] ";}puts("");}

#define read2d(a,w,h)   rep(i,h)rep(j,w)cin>>a[i][j]
#define dump2d(a,w,h)   rep(i,h){rep(j,w)cout<<a[i][j]<<" ";puts("");}

typedef pair<li, li> PI;

li n;
string s[55];
string sr[55];
li c[55];

inline bool is_par(string& x) {
    string xx = x;
    reverse(allof(xx));
    return xx == x;
}

int main() {
    cin >> n;
    rin{
        cin >> s[i] >> c[i];
        sr[i] = s[i];
        reverse(allof(sr[i]));
    }

    priority_queue<pair<li, pair<string, string>>> pq;
    rin{
        pq.push({ -c[i], {s[i], ""}});
    }

    set<pair<string, string>> visited;

    while (!pq.empty()) {
        li now_cost = -pq.top().F;
        string l = pq.top().S.F;
        string r = pq.top().S.S;
        pq.pop();
        //p2(now_cost, now);
        if ((l.empty() && is_par(r)) || (r.empty() && is_par(l))) {
            cout << now_cost << endl;
            return 0;
        }
        if (visited.count({l, r}) > 0) {
            continue;
        }
        visited.insert({l, r});
        if (l.empty()) {
            string rr = r;
            reverse(allof(rr));
            rin {
                if (sz(s[i]) <= sz(rr)) {
                    if (s[i] == rr.substr(0, sz(s[i]))) {
                        string rest = rr.substr(sz(s[i]));
                        reverse(allof(rest));
                        pq.push({ -now_cost - c[i], {"", rest}});
                    }
                } else {
                    if (rr == s[i].substr(0, sz(rr))) {
                        pq.push({ -now_cost - c[i], {s[i].substr(sz(rr)), ""}});
                    }
                }
            }
        } else {
            // r is empty
            rin{
                string sir = s[i];
                reverse(allof(sir));
                if (sz(sir) <= sz(l)) {
                    if (sir == l.substr(0, sz(sir))) {
                        pq.push({ -now_cost - c[i], {l.substr(sz(sir)), ""}});
                    }
                } else {
                    if (sir.substr(0, sz(l)) == l) {
                        string rest = sir.substr(sz(l));
                        reverse(allof(rest));
                        pq.push({ -now_cost - c[i], {"", rest}});
                    }
                }
            }
        }
    }
    cout << -1 << endl;


    return 0;
}

Measured memory_bytes: 3728