///////////////////////////////////////////////////////////////////////////////

#include <bits/stdc++.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>

using namespace std;

///////////////////////////////////////////////////////////////////////////////

#define DEBUG 0

#define pb push_back
#define V vector
#define M unordered_map
#define S static

#define rep(i,n) for(ll i=0LL; i<n; ++i)
#define srep(i,s,n) for(ll i=s; i<n; ++i)
#define rrep(i,n) for(ll i=n-1LL; i>=0LL; --i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define CIN(x) do { \
        assert(!cin.eof()); \
        cin >> x; \
        assert(!cin.fail()); \
} while(0);
#if DEBUG
#define debug_print(...) _debug_print(__VA_ARGS__)
#define debug_printf(...) printf(__VA_ARGS__)
#define debug_print_time _debug_print_time
#else // DEBUG
#define debug_print(...)
#define debug_printf(...)
#define debug_print_time
#endif // DEBUG

typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll, ll> t2;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;
template <typename T>
using priority_queue_incr = priority_queue<T, V<T>, greater<T> >;

///////////////////////////////////////////////////////////////////////////////

template <typename TT, typename T>
T get_m(M<TT, T> &m, TT k, T default_value)
{
    if (m.find(k) == m.end()) return m[k] = default_value;
    return m[k];
}

template <typename TT, typename T>
void incr_m(M<TT, T> &m, TT k)
{
    if (m.find(k) == m.end()) m[k] = 0;
    m[k]++;
}

template <typename TT, typename T>
void incr_m(map<TT, T> &m, TT k)
{
    if (m.find(k) == m.end()) m[k] = 0;
    m[k]++;
}

void llin(ll &a)
{
    CIN(a);
}

void llinl1(V<ll> &v, ll count)
{
    for (ll i = 0LL; i < count; ++i) {
        ll a;
        CIN(a);
        v.push_back(a);
    }
}

void llinl2(V<t2> &v, ll count)
{
    for (ll i = 0LL; i < count; ++i) {
        ll a, b;
        CIN(a >> b);
        v.push_back(t2(a, b));
    }
}

void llinl3(V<t3> &v, ll count)
{
    for (ll i = 0LL; i < count; ++i) {
        ll a, b, c;
        CIN(a >> b >> c);
        v.push_back(t3(a, b, c));
    }
}

void llinl4(V<t4> &v, ll count)
{
    for (ll i = 0LL; i < count; ++i) {
        ll a, b, c, d;
        CIN(a >> b >> c >> d);
        v.push_back(t4(a, b, c, d));
    }
}

void llina(V<ll> &v, ll count)
{
    llinl1(v, count);
}

template <typename T>
void sort(V<T> &v)
{
    sort(v.begin(), v.end());
}

template <typename T>
void sort_reverse(V<T> &v)
{
    sort(v.begin(), v.end(), greater<T>());
}

template <typename T>
void _debug_print(T x)
{
    cout << x << endl;
}

void _debug_print(const t2 &x)
{
    ll x1 = get<0>(x);
    ll x2 = get<1>(x);
    cout << "-- " << x1 << " -- " << x2 << endl;
}

void _debug_print(const t3 &x)
{
    ll x1 = get<0>(x);
    ll x2 = get<1>(x);
    ll x3 = get<2>(x);
    cout << "-- " << x1 << " -- " << x2 << " -- " << x3 << endl;
}

void _debug_print(const t4 &x)
{
    ll x1 = get<0>(x);
    ll x2 = get<1>(x);
    ll x3 = get<2>(x);
    ll x4 = get<3>(x);
    cout << "-- " << x1 << " -- " << x2
         << " -- " << x3 << " -- " << x4 << endl;
}

template <typename T>
void _debug_print(T xarray[], ll n)
{
    rep (i, n) _debug_print(xarray[i]);
}

template <typename T>
void _debug_print(const V<T> &xlist)
{
    for (auto x : xlist) {
        cout << "-- ";
        _debug_print(x);
    }
}

template <typename T>
void _debug_print(const set<T> &xset)
{
    for (auto x : xset) {
        cout << "-- ";
        _debug_print(x);
    }
}

template <typename TT, typename T>
void _debug_print(const M<TT, T> &xlist)
{
    for (auto x : xlist) {
        TT k = x.first;
        T v = x.second;
        cout << "====" << endl;
        cout << "K=";
        _debug_print(k);
        cout << "V=";
        _debug_print(v);
    }
}

template <typename TT, typename T>
void _debug_print(const map<TT, T> &xlist)
{
    for (auto x : xlist) {
        TT k = x.first;
        T v = x.second;
        cout << "====" << endl;
        cout << "K=";
        _debug_print(k);
        cout << "V=";
        _debug_print(v);
    }
}

void _debug_print_time(const char *prefix)
{
    struct timeval tv;
    gettimeofday(&tv, NULL);
#if DEBUG
    struct tm *tm = localtime(&tv.tv_sec);
#endif
    debug_printf("-- %s %02d:%02d:%02d.%06ld\n",
                 prefix, tm->tm_hour, tm->tm_min, tm->tm_sec, tv.tv_usec);
}

///////////////////////////////////////////////////////////////////////////////

void _main();
int main()
{
    cout << setprecision(12);
#if !DEBUG
    ios::sync_with_stdio(false);
    cin.tie(0);
#endif

    _main();
    return 0;
}

typedef tuple<string, ll> sll;

bool palin(const string &s)
{
    bool ret = true;
    ll len = s.size();
    rep (i, len/2) if (s[i] != s[len-i-1]) ret = false;
    return ret;
}

void _main()
{
    ll n; llin(n);
    V<sll> sclist;
    rep (i, n) {
        string s; CIN(s);
        ll c; llin(c);
        sclist.pb(sll(s, c));
    }

    ll ans = 1e18;

    rep (i, n) {
        string s = get<0>(sclist[i]);
        ll c = get<1>(sclist[i]);

        debug_printf("------------ start s=%s\n", s.c_str());

        priority_queue_incr<tuple<ll, sll> > q;
        set<sll> checked;
        q.push(tuple<ll, sll>(c, sll(s, 0)));

        while (q.size()) {
            auto item = q.top(); q.pop();
            ll cost = get<0>(item);
            sll xx = get<1>(item);
            string s1 = get<0>(xx);
            ll dir = get<1>(xx);

            if (checked.find(xx) != checked.end()) continue;
            checked.insert(xx);

            if (palin(s1)) {
                ans = min(ans, cost);
                break;
            }

            if (dir == 0) {
                rep (j, n) {
                    auto item2 = sclist[j];
                    string s2 = get<0>(item2);
                    ll c2 = get<1>(item2);
                    ll diff = abs((ll)s1.size() - (ll)s2.size());

                    if (s1.size() < s2.size()) {
                        string s2l = s2.substr(diff);
                        reverse(ALL(s2l));
                        if (s1 != s2l) continue;
                        q.push(tuple<ll, sll>(cost + c2, sll(s2.substr(0, diff), 1)));
                    }
                    else {
                        string s1l = s1.substr(0, s2.size());
                        reverse(ALL(s1l));
                        if (s1l != s2) continue;
                        q.push(tuple<ll, sll>(cost + c2, sll(s1.substr(s2.size()), 0)));
                    }
                }
            }
            else {
                rep (j, n) {
                    auto item2 = sclist[j];
                    string s2 = get<0>(item2);
                    ll c2 = get<1>(item2);
                    ll diff = abs((ll)s1.size() - (ll)s2.size());

                    if (s2.size() < s1.size()) {
                        string s1l = s1.substr(diff);
                        reverse(ALL(s1l));
                        if (s2 != s1l) continue;
                        q.push(tuple<ll, sll>(cost + c2, sll(s1.substr(0, diff), 1)));
                    }
                    else {
                        string s2l = s2.substr(0, s1.size());
                        reverse(ALL(s2l));
                        if (s2l != s1) continue;
                        q.push(tuple<ll, sll>(cost + c2, sll(s2.substr(s1.size()), 0)));
                    }
                }
            }
        }
    }

    debug_printf("----------------- ans\n");
    if (ans > 1e17) ans = -1;
    cout << ans << endl;
}

///////////////////////////////////////////////////////////////////////////////


Measured memory_bytes: 3656