#define CPP17
#include <limits>
#include <initializer_list>
#include <utility>
#include <bitset>
#include <tuple>
#include <type_traits>
#include <functional>
#include <string>
#include <array>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <iterator>
#include <algorithm>
#include <complex>
#include <random>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <regex>
#include <cassert>
#include <cstddef>
#ifdef CPP17
#include <variant>
#endif

#define endl codeforces

#define ALL(v) std::begin(v), std::end(v)
#define ALLR(v) std::rbegin(v), std::rend(v)

using ll = std::int64_t;
using ull = std::uint64_t;
using pii = std::pair<int, int>;
using tii = std::tuple<int, int, int>;
using pll = std::pair<ll, ll>;
using tll = std::tuple<ll, ll, ll>;
using size_type = ssize_t;
template <typename T> using vec = std::vector<T>;
template <typename T> using vvec = vec<vec<T>>;

template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }

template <typename T, std::size_t Head, std::size_t... Tail> 
struct multi_dim_array { using type = std::array<typename multi_dim_array<T, Tail...>::type, Head>; };

template <typename T, std::size_t Head> 
struct multi_dim_array<T, Head> { using type = std::array<T, Head>; };

template <typename T, std::size_t... Args> using mdarray = typename multi_dim_array<T, Args...>::type;

#ifdef CPP17
template <typename T, typename F, typename... Args> 
void fill_seq(T &t, F f, Args... args) { 
    if constexpr (std::is_invocable<F, Args...>::value) { 
        t = f(args...); 
    } else { 
        for (size_type i = 0; i < t.size(); i++) fill_seq(t[i], f, args..., i); 
    } 
}
#endif

template <typename T> vec<T> make_v(size_type sz) { return vec<T>(sz); }

template <typename T, typename... Tail> 
auto make_v(size_type hs, Tail&&... ts) { 
    auto v = std::move(make_v<T>(std::forward<Tail>(ts)...)); 
    return vec<decltype(v)>(hs, v); 
}

namespace init__ { 
struct InitIO { 
    InitIO() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(30); } 
} init_io; 
}
#define CPP17


int main() {
    const ll inf = 5e15;
    ll n;
    std::cin >> n;
    vec<std::string> sv(n);
    vec<ll> cv(n);
    for (ll i = 0; i < n; i++) std::cin >> sv[i] >> cv[i];

    vec<ll> szv(n);
    for (ll i = 0; i < n; i++) szv[i] = sv[i].size();

    std::map<pll, ll> id;
    for (ll i = 0; i < n; i++) {
        for (ll j = 0; j < szv[i]; j++) {
            ll sz = id.size();
            id[pll(i, j)] = sz;
            id[pll(i, -(j + 1))] = sz;
        }
    }

    auto is_pal = [&](ll i, ll j, ll k) {
        const auto &s = sv[i];
        while (j < k) {
            if (s[j] != s[k]) return false;
            j++;
            k--;
        }
        return true;
    };

    auto to_goal = [&](pll p) {
        auto [ a, b ] = p;
        if (0 <= b) return is_pal(a, b, szv[a] - 1);
        else return is_pal(a, 0, szv[a] + b);
    };

    auto check_concat = [&](pll p, ll i) {
        auto [ a, b ] = p;
        const auto &s1 = sv[a], &s2 = sv[i];
        ll sz1 = szv[a], sz2 = szv[i];
        if (0 <= b) {
            ll idx = -1;
            while (b < sz1 && 0 <= sz2 + idx) {
                if (s1[b] != s2[sz2 + idx]) return false;
                b++;
                idx--;
            }
        } else {
            ll idx = 0;
            while (0 <= sz1 + b && idx < sz2) {
                if (s1[sz1 + b] != s2[idx]) return false;
                b--;
                idx++;
            }
        }
        return true;
    };

    pll src_p(-1, -1), dst_p(-1, -2);
    {
        ll tmp = id.size();
        id[src_p] = tmp;
        id[dst_p] = tmp + 1;
    }
    vec<ll> dist(id.size() + 1, inf);
    dist[id[src_p]] = 0;
    using value_type = std::pair<ll, pll>;
    std::priority_queue<value_type, vec<value_type>, std::greater<value_type>> pq;
    for (ll i = 0; i < n; i++) {
        pll p1(i, 0), p2(i, -1);
        ll id1 = id[p1];
        ll id2 = id[p2];
        dist[id1] = dist[id2] = cv[i];
        pq.emplace(cv[i], p1);
        pq.emplace(cv[i], p2);
    }

    auto add_pq = [&](pll p, ll d) {
        ll i = id[p];
        if (d < dist[i]) {
            dist[i] = d;
            pq.emplace(d, p);
        }
    };

    while (pq.size()) {
        auto [ c, p ] = pq.top();
        pq.pop();
        ll pid = id[p];
        if (dist[pid] < c) continue;
        if (p == dst_p) break;
        if (to_goal(p)) add_pq(dst_p, c);

        
        auto [ a, b ] = p;
        
        for (ll i = 0; i < n; i++) {
            if (!check_concat(p, i)) continue;
            ll nd = c + cv[i];
            if (0 <= b) {
                ll sz1 = szv[a] - b;
                ll sz2 = szv[i];
                if (sz1 < sz2) add_pq(pll(i, -1 - sz1), nd);
                if (sz1 > sz2) add_pq(pll(a, b + sz2), nd);
                if (sz1 == sz2) add_pq(dst_p, nd);
            } else {
                ll sz1 = szv[a] + b + 1;
                ll sz2 = szv[i];
                if (sz1 < sz2) add_pq(pll(i, sz1), nd);
                if (sz1 > sz2) add_pq(pll(a, b - sz2), nd);
                if (sz1 == sz2) add_pq(dst_p, nd);
            }
        }
    }

    ll ans = dist[id[dst_p]];
    if (ans == inf) ans = -1;
    std::cout << ans << "\n";
    return 0;
}


Measured memory_bytes: 3776