#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC push_options
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#include<bits/stdc++.h>
#include <xmmintrin.h>
#include <immintrin.h>
using namespace::std;
__attribute__((constructor))void init(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<0>> cdouble;
// typedef mp::cpp_int cint;
template<typename T>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T,typename E>using hash_map=__gnu_pbds::gp_hash_table<T,E>;
template<typename T>using pqueue =__gnu_pbds::priority_queue<T, greater<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define LINF (9223372036854775807LL)
#define EPS (1e-10)
#define endl ('\n')
#define MOD 1000000007LL
//#define MOD 998244353LL
//#define MOD 18446744069414584321ULL
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(lint i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(lint i=0;i<t.size();i++)output(t[i]);}
#define rep(i,...) for(auto i:range(__VA_ARGS__)) 
#define rrep(i,...) for(auto i:reversed(range(__VA_ARGS__)))
#define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
#define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
#define irep(i) for(lint i=0;;++i)
inline vector<int64_t> range(int64_t n){vector<int64_t>v(n);iota(v.begin(),v.end(),0LL);return v;}
inline vector<int64_t> range(int64_t a,int64_t b){vector<int64_t>v(b-a);iota(v.begin(),v.end(),a);return v;}
inline vector<int64_t> range(int64_t a,int64_t b,int64_t c){vector<int64_t>v((b-a+c-1)/c);for(int i=0;i<(int)v.size();++i)v[i]=i?v[i-1]+c:a;return v;}
inline auto reversed(auto v){reverse(v.begin(),v.end());return v;}
#define all(n) begin(n),end(n)
#define dist(a,b,c,d) sqrt(pow(a-c,2)+pow(b-d,2))
//inline lint gcd(lint A,lint B){return B?gcd(B,A%B):A;}
//inline lint lcm(lint A,lint B){return A/gcd(A,B)*B;}
// inline cint cgcd(cint A,cint B){return B?cgcd(B,A%B):A;}
// inline cint clcm(cint A,cint B){return A/cgcd(A,B)*B;}
bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
auto call=[](auto f,auto... args){return f(f,args...);};
template<typename T,typename ...Args>auto make_vector(T x,int arg,Args ...args){if constexpr(sizeof...(args)==0)return vector<T>(arg,x);else return vector(arg,make_vector<T>(x,args...));}

struct rolling_hash{
    using u64=uint64_t;
    constexpr static u64 mod=(1ULL<<61)-1;
    constexpr static u64 base=10007;
    int sz;
    u64 hash;
    constexpr rolling_hash():sz(0),hash(0){}
    constexpr rolling_hash(char c):sz(1),hash(c){}
    rolling_hash(string s):sz(0),hash(0){
        for(auto c:s)(*this)+=c;
    }
    constexpr u64 pow(u64 s,int t){
        u64 ret=1;
        while(t){
            if(t&1)ret=mul(ret,s);
            s=mul(s,s);
            t/=2;
        }
        return ret;
    }
    constexpr u64 add(u64 s,u64 t)noexcept{
        s+=t;
        return s>=mod?s-mod:s;
    }
    constexpr u64 sub(u64 s,u64 t)noexcept{
        if(s<t)s+=mod;
        return s-t;
    }
    constexpr u64 mul(u64 a,u64 b)noexcept{
        u64 au=a>>31,ad=a&((1ULL<<31)-1);
        u64 bu=b>>31,bd=b&((1ULL<<31)-1);
        u64 mid=au*bd+ad*bu;
        u64 ret=(au*bu*2+ad*bd+(mid>>30)+((mid&((1ULL<<30)-1))<<31));
        ret=(ret>>61)+(ret&mod);
        return ret>=mod?ret-mod:ret;
    }
    constexpr rolling_hash operator+(rolling_hash s)const noexcept{return rolling_hash(*this)+=s;}
    constexpr bool operator==(rolling_hash s)noexcept{return hash==s.hash&&sz==s.sz;}
    constexpr bool operator<(rolling_hash s)const noexcept{return make_pair(hash,sz)<make_pair(s.hash,s.sz);}
    constexpr bool operator>(rolling_hash s)const noexcept{return make_pair(hash,sz)>make_pair(s.hash,s.sz);}
    constexpr bool operator<=(rolling_hash s)const noexcept{return make_pair(hash,sz)<=make_pair(s.hash,s.sz);}
    constexpr bool operator>=(rolling_hash s)const noexcept{return make_pair(hash,sz)>=make_pair(s.hash,s.sz);}
    constexpr rolling_hash operator+=(rolling_hash s)noexcept{
        (*this).hash=add((*this).hash*pow(base,s.sz),s.hash);
        (*this).sz+=s.sz;
        return *this;
    }
    constexpr int size(){return sz;}
};

int main(){
    lint n;
    cin>>n;
    priority_queue<tuple<lint,string,lint>,vector<tuple<lint,string,lint>>,greater<tuple<lint,string,lint>>>que;
    map<pair<string,lint>,lint>m;
    vector<string>s(n);
    vector<lint>c(n);
    rep(i,n){
        cin>>s[i]>>c[i];
    }
    que.emplace(0,"",0);
    que.emplace(0,"",1);
    auto f=[&](string s,lint b,string t)->pair<string,lint>{
        if(b==0){
            reverse(all(t));
            rep(i,min(s.size(),t.size())){
                if(s[i]!=t[i])return {"",2};
            }
            if(s.size()<t.size()){
                return {t.substr(s.size(),t.size()-s.size()),1};
            }
            else return {s.substr(t.size(),s.size()-t.size()),0};
        }else{
            rep(i,min(s.size(),t.size())){
                if(s[i]!=t[i])return {"",2};
            }
            if(s.size()<t.size())return {t.substr(s.size(),t.size()-s.size()),0};
            else return {s.substr(t.size(),s.size()-t.size()),1};
        }
    };
    while(!que.empty()){
        auto [co,st,b]=que.top();
        que.pop();
        if(st==string(st.rbegin(),st.rend())&&co){
            cout<<co<<endl;
            return 0;
        }
        rep(i,n){
            auto to=f(st,b,s[i]);
            if(to.second==2)continue;
            if(m.count(to)==0||m[to]>co+c[i]){
                que.emplace(m[to]=co+c[i],to.first,to.second);
            }
        }
    }
    cout<<-1<<endl;
}

Measured memory_bytes: 3764