#ifndef AUTO_UTIL_HEADER_HPP
#define AUTO_UTIL_HEADER_HPP

#include <bits/stdc++.h>
#include <cassert>

using std::cin, std::cout, std::bitset, std::complex;
using std::vector, std::array, std::string, std::pair, std::list, std::queue, std::deque;
using std::priority_queue, std::set, std::map, std::unordered_map;
using std::sort, std::greater, std::min, std::max, std::reverse;
using std::min_element, std::max_element, std::accumulate;

using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using ull = unsigned long long int;
using ll = long long int;
using vll = vector<ll>; using vvll = vector<vll>; using vvvll = vector<vvll>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using cdouble = complex<double>;

const double eps = 1e-7;
#define Loop(i, n) for(int i = 0; i < int(n); i++)
#define Loopll(i, n) for(ll i = 0; i < ll(n); i++)
#define Loop1(i, n) for(int i = 1; i <= int(n); i++)
#define Loopll1(i, n) for(ll i = 1; i <= ll(n); i++)
#define Loopr(i, n) for(int i = int(n) - 1; i >= 0; i--)
#define Looprll(i, n) for(ll i = ll(n) - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = int(n); i >= 1; i--)
#define Looprll1(i, n) for(ll i = ll(n); i >= 1; i--)
#define Foreach(buf, container) for(const auto &buf : container)
#define Foreachr(buf, container)  for(const auto &buf : reversed(container))
#define Loopdiag(i, j, h, w, sum) for(int i = ((sum) >= (h) ? (h) - 1 : (sum)), j = (sum) - i; i >= 0 && j < (w); i--, j++)
#define Loopdiagr(i, j, h, w, sum) for(int j = ((sum) >= (w) ? (w) - 1 : (sum)), i = (sum) - j; j >= 0 && i < (h); j--, i++)
#define Loopdiagsym(i, j, h, w, gap) for (int i = ((gap) >= 0 ? (gap) : 0), j = i - (gap); i < (h) && j < (w); i++, j++)
#define Loopdiagsymr(i, j, h, w, gap) for (int i = ((gap) > (h) - (w) - 1 ? (h) - 1 : (w) - 1 + (gap)), j = i - (gap); i >= 0 && j >= 0; i--, j--)
#define Loopitr(itr, container) for(auto itr = container.begin(); itr != container.end(); itr++)
#define quickio() std::ios::sync_with_stdio(false); std::cin.tie(0);
#define bitmanip(m,val) static_cast<bitset<(int)m>>(val)
#define Comp(type_t) bool operator<(const type_t &another) const
#define fst first
#define snd second
bool feq(double x, double y) { return abs(x - y) <= eps; }
bool inrange(ll x, ll t) { return x >= 0 && x < t; }
bool inrange(vll xs, ll t) { Foreach(x, xs) if (!(x >= 0 && x < t)) return false; return true; }
int ceillog2(ll x) { int m = int(log2(x)); return m + ((1LL << m) < x ? 1 : 0); }
int floorlog2(ll x) { int m = int(log2(x)); return m - ((1LL << m) > x ? 1 : 0); }
const string endl = "\n";
template<class T> T reversed(T container) { reverse(container.begin(), container.end()); return container; }
template<class T> void printv(const vector<T> &v) { for (const T &x : v) cout << x << " "; cout << endl; }
template<class T> void printmx(const vector<vector<T>> &mx) { for (const vector<T> &v : mx) printv(v); }
ll rndf(double x) { return (ll)(x + (x >= 0 ? 0.5 : -0.5)); }
ll floorsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (m*  m <= x ? 0 : -1); }
ll ceilsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (x <= m * m ? 0 : 1); }
ll rnddiv(ll a, ll b) { return (a / b + (a % b * 2 >= b ? 1 : 0)); }
ll ceildiv(ll a, ll b) { return (a / b + (a % b == 0 ? 0 : 1)); }
ll gcd(ll m, ll n) { if (n == 0) return m; else return gcd(n, m % n); }
ll lcm(ll m, ll n) { return ll(m) * ll(n) / gcd(m, n); }

#endif // AUTO_UTIL_HEADER_HPP

//========================================================================//

class Dijkstra {
private:
	struct node {
		int id; bool done; vi to; vll cst; int from; ll d;
	};
	struct pq_t {
		int id; ll d;
		bool operator<(const pq_t & another) const {
			return d != another.d ? d > another.d : id > another.id;
		}
	};
	vector<node> nodes;
	int n, m, source;
public:
	Dijkstra(const vvi &lst, const vvll &cst, int start) {
		n = lst.size();
		nodes.resize(n);
		Loop(i, n) nodes[i] = { i, false,{},{}, -1, LLONG_MAX };
		Loop(i, n) {
			Loop(j, lst[i].size()) {
				nodes[i].to.push_back(lst[i][j]);
				nodes[i].cst.push_back(cst[i][j]);
			}
		}
		source = start;
		nodes[source].d = 0;
		priority_queue<pq_t> pq;
		pq.push({ nodes[source].id, nodes[source].d });
		while (pq.size()) {
			int a = pq.top().id;
			pq.pop();
			if (nodes[a].done) continue;
			nodes[a].done = true;
			Loop(j, nodes[a].to.size()) {
				int b = nodes[a].to[j];
				if (nodes[b].done) continue;
				ll buf = nodes[a].d + nodes[a].cst[j];
				if (buf < nodes[b].d) {
					nodes[b].d = buf;
					nodes[b].from = a;
					pq.push({ b, nodes[b].d });
				}
			}
		}
		return;
	}
	vi get_path(int v) {
		vi stk;
		stk.push_back(v);
		int a = v;
		while (nodes[a].from != -1) {
			stk.push_back(nodes[a].from);
			a = nodes[a].from;
		}
		if (a != source) return {};
		vi ret;
		while (stk.size()) {
			ret.push_back(stk.back());
			stk.pop_back();
		}
		return ret;
	}
	ll get_dist(int v) {
		return nodes[v].d;
	}
};

bool is_parlindrome(const string &s) {
    int n = s.length();
    Loop(i, n >> 1) {
        if (s[i] != s[n - 1 - i]) return false;
    }
    return true;
}

int main() {
    using index_t = array<ll, 3>;
    struct edge_t {
        int s, t;
        ll c;
    };
    int n; cin >> n;
    vector<string> s(n);
    vll c(n);
    Loop(i, n) {
        cin >> s[i];
        cin >> c[i];
    }
    map<index_t, int> encoder;
    int ncode = 0;
    encoder[{-1, -1, -1}] = ncode++;
    Loop(i, n) {
        Loop(j, s[i].length()) {
            Loop(k, 2) {
                // cout << i << " " << j << " " << k << " " << ncode << endl;
                encoder[{i, j, k}] = ncode++;
            }
        }
    }
    vector<edge_t> edges;
    Loop(i0, n) {
        Loop(j0, s[i0].length()) {
            Loop(i1, n) {
                int p = j0;
                int q = s[i1].length() - 1;
                int failed_flag = 0;
                for (; p < s[i0].length() && q >= 0; p++, q--) {
                    if (s[i0][p] != s[i1][q]) {
                        failed_flag = 1;
                        break;
                    }
                }
                if (failed_flag) continue;
                else if (p == s[i0].length() && q == -1) {
                    edges.push_back({0, encoder[{i0, j0, 0}], c[i1]});
                }
                else if (p == s[i0].length()) {
                    if (is_parlindrome(s[i1].substr(0, q + 1))) {
                        edges.push_back({0, encoder[{i0, j0, 0}], c[i1]});
                    }
                    else {
                        edges.push_back({encoder[{i1, q, 1}], encoder[{i0, j0, 0}], c[i1]});
                    }
                }
                else {
                    if (is_parlindrome(s[i0].substr(p, 100))) {
                        edges.push_back({0, encoder[{i0, j0, 0}], c[i1]});
                    }
                    else {
                        edges.push_back({encoder[{i0, p, 0}], encoder[{i0, j0, 0}], c[i1]});
                    }
                }
            }
            Loop(i1, n) {
                int q = j0;
                int p = 0;
                int failed_flag = 0;
                for (; p < s[i1].length() && q >= 0; p++, q--) {
                    if (s[i0][q] != s[i1][p]) {
                        failed_flag = 1;
                        break;
                    }
                }
                if (failed_flag) continue;
                else if (p == s[i1].length() && q == -1) {
                    edges.push_back({0, encoder[{i0, j0, 1}], c[i1]});
                }
                else if (p == s[i1].length()) {
                    if (is_parlindrome(s[i0].substr(0, q + 1))) {
                        edges.push_back({0, encoder[{i0, j0, 1}], c[i1]});
                    }
                    else {
                        edges.push_back({encoder[{i0, q, 1}], encoder[{i0, j0, 1}], c[i1]});
                    }
                }
                else {
                    if (is_parlindrome(s[i1].substr(p, 100))) {
                        edges.push_back({0, encoder[{i0, j0, 1}], c[i1]});
                    }
                    else {
                        edges.push_back({encoder[{i1, p, 0}], encoder[{i0, j0, 1}], c[i1]});
                    }
                }    
            }
        }
    }
    ll ans = LLONG_MAX;
    Loop(i, n) {
        if (is_parlindrome(s[i])) {
            ans = min(ans, c[i]);
        }
    }
    vvi lst(ncode);
    vvll cst(ncode);
    for (const auto &edge : edges) {
        lst[edge.s].push_back(edge.t);
        cst[edge.s].push_back(edge.c);
    }
    Dijkstra *dijk = new Dijkstra(lst, cst, 0);
    Loop(i, n) {
        ll buf0 = dijk->get_dist(encoder[{i, 0, 0}]);
        ll buf1 = dijk->get_dist(encoder[{i, s[i].length() - 1, 1}]);
        if (buf0 < LLONG_MAX) ans = min(ans, c[i] + buf0);
        if (buf1 < LLONG_MAX) ans = min(ans, c[i] + buf1);
    }
    if (ans < LLONG_MAX) cout << ans << endl;
    else cout << -1 << endl;
    delete dijk;
}

Measured memory_bytes: 4112