#include <bits/stdc++.h>
 
//    #include <boost/multiprecision/cpp_int.hpp>
 #define int long long
 #define inf  1000000007
// #define inf  998244353

 #define pa pair<int,int>
 #define ll long long
 #define pal pair<double,double>
 #define ppap pair<pa,int>
  #define PI 3.14159265358979323846
  #define paa pair<int,char>
  #define  mp make_pair
  #define  pb push_back
  #define EPS (1e-8)
                                          
    int dx[8]={0,1,0,-1,1,1,-1,-1};
    int dy[8]={1,0,-1,0,-1,1,1,-1};
                                            using namespace std;
                                   			class pa3{
                                            	public:
                                            	int x;
                                   				int y,z;
                                            	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                            	bool operator < (const pa3 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		 return z<p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                   				bool operator > (const pa3 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		 return z>p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa3 &p) const{
                                            		return x==p.x && y==p.y && z==p.z;
                                            	}
                                            		bool operator != (const pa3 &p) const{
                                            			return !( x==p.x && y==p.y && z==p.z);
                                            	}
                                            
                                            };
                                            
                                            class pa4{
                                            	public:
                                            	int x;
                                            	int y,z,w;
                                            	pa4(int x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                            	bool operator < (const pa4 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		if(z!=p.z)return z<p.z;
                                            		return w<p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator > (const pa4 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		if(z!=p.z)return z>p.z;
                                            		return w>p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa4 &p) const{
                                            		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                            	}
                                            		
                                            
                                            };
                                            class pa2{
                                            	public:
                                            	int x,y;
                                            	pa2(int x=0,int y=0):x(x),y(y) {}
                                            	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                            	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                            	bool operator < (const pa2 &p) const{
                                            		return y != p.y ? y<p.y: x<p.x;
                                            	}
                                            	bool operator > (const pa2 &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa2 &p) const{
                                            		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                            	}
                                            	bool operator != (const pa2 &p) const{
                                            		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                            	}
                                            		
                                            
                                            };
                                            
 
                      
                                string itos( int i ) {
                                ostringstream s ;
                                s << i ;
                                return s.str() ;
                                }
                                 
                                int Gcd(int v,int b){
                                	if(v==0) return b;
                                	if(b==0) return v;
                                	if(v>b) return Gcd(b,v);
                                	if(v==b) return b;
                                	if(b%v==0) return v;
                                	return Gcd(v,b%v);
                                }
                 
                            
                                int mod;
int extgcd(int a, int b, int &x, int &y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    int d = extgcd(b, a%b, y, x);
    y -= a/b * x;
    return d;
}
pa operator+(const pa & l,const pa & r) {   
    return {l.first+r.first,l.second+r.second};                                    
}    
pa operator-(const pa & l,const pa & r) {   
    return {l.first-r.first,l.second-r.second};                                    
}  
                int beki(int wa,int rr,int warukazu){
                	if(rr==0) return 1%warukazu;
                	if(rr==1) return wa%warukazu;
                	wa%=warukazu;
                	if(rr%2==1) return ((ll)beki(wa,rr-1,warukazu)*(ll)wa)%warukazu;
                	ll zx=beki(wa,rr/2,warukazu);
                	return (zx*zx)%warukazu;
                }
 
                              
                int pr[100000];
                int inv[100000];
                

                
    			int comb(int nn,int rr){
    				if(rr<0 || rr>nn || nn<0) return 0;
    				int r=pr[nn]*inv[rr];
    				r%=mod;
    				r*=inv[nn-rr];
    				r%=mod;
    				return r;
    			}
               
                void gya(int ert){
                	pr[0]=1;
                	for(int i=1;i<=ert;i++){
                		pr[i]=((ll)pr[i-1]*i)%mod;
                	}
                		inv[ert]=beki(pr[ert],mod-2,mod);
                	for(int i=ert-1;i>=0;i--){
                		inv[i]=(ll)inv[i+1]*(i+1)%mod;
                	}
                }
                
              //   cin.tie(0);
    		//	ios::sync_with_stdio(false);
    			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
                 //sort(ve.begin(),ve.end(),greater<int>());
 //   mt19937(clock_per_sec);
  //  mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()) ;
map<pair<string,int>,int> ma;

bool man(string s,int c){
	for(int j=1;c-j>=0 && c+j<(int)s.length();j++){
		if(s[c+j]!=s[c-j])return 0;
	}
//	if(s.length()%2==1 && s.length()/2==c)return 0;
	return 1;
}
bool man2(string s,int c){
	for(int j=1;c-j>=0 && c+j-1<(int)s.length();j++){
		if(s[c+j-1]!=s[c-j])return 0;
	}
//	if(s.length()%2==0 && s.length()/2==c)return 0;
	return 1;
}
int lcp(string s,string t){
	int cnt=0;
	for(int i=0;;i++){
		if(i>=(int)s.length())break;
		if(i>=(int)t.length())break;
		if(s[i]!=t[i])break;
		cnt++;
	}
	return cnt;
}
vector<int> C;

vector<string>S,T;
vector<int> len;
set<pair<string,int>>dame;
int solve(string s,int ty,int n){
	if(s=="")return 0;
	
	if(dame.count(mp(s,ty)))return inf*1000000000ll;
	if(ma.count(mp(s,ty)))return ma[mp(s,ty)];
	dame.insert(mp(s,ty));
//	cout<<s<<" "<<ty<<endl;
	int l=s.length();
	int ans=inf*1000000000ll;
	if(ty==2){
		for(int i=0;i<n;i++){
			int g=lcp(S[i],s);
			if(len[i]==l){
				if(g==l)ans=min(ans,C[i]);
			}
			else if(len[i]>l){
				if(g==l){
					ans=min(ans,C[i]+solve(S[i].substr(l),1,n));
				}
			}
			else if(len[i]<l){
				if(g==len[i]){
					ans=min(ans,C[i]+solve(s.substr(len[i]),2,n));
				}
			}
		}
	}
	else{
		for(int i=0;i<n;i++){
			int g=lcp(T[i],s);
			if(len[i]==l){
				if(g==l)ans=min(ans,C[i]);
			}
			else if(len[i]>l){
				
				if(g==l){
					ans=min(ans,C[i]+solve(T[i].substr(l),2,n));
				}
			}
			else if(len[i]<l){
				if(g==len[i]){
					ans=min(ans,C[i]+solve(s.substr(len[i]),1,n));
				}
			}
		}
		
	}
//	cout<<"!! "<<s<<" "<<ty<<"  "<<ans<<endl;
	dame.erase(mp(s,ty));
	ma[mp(s,ty)]=ans;
	return ans;
}

void solve(){
	int n;
	cin>>n;
		vector<string> s(n),t(n);
	int ans=inf*100000000ll;
	for(int i=0;i<n;i++){
		cin>>s[i];
		t[i]=s[i];
		int y;
		cin>>y;
		C.pb(y);
		len.pb(s[i].length());
		reverse(t[i].begin(),t[i].end());
		if(t[i]==s[i])ans=min(ans,C[i]);
	}
	S=s,T=t;
	int pp=0;
	for(auto c:s){
			int l=c.length();
		for(int i=0;i<c.length();i++)if(man(c,i)){

			int mae=i;
		
			int ato=l-mae-1;
			
			if(mae<ato){
		//		cout<<c.substr(mae*2+1)<<endl;
				ans=min(ans,C[pp]+solve(c.substr(mae*2+1),1,n));
			}
			else{
				string tm=c.substr(0,l-2*ato-1);
				reverse(tm.begin(),tm.end());
		//		cout<<tm<<endl;
				ans=min(ans,C[pp]+solve(tm,2,n));
			}
			
		}
		for(int i=0;i<=l;i++)if(man2(c,i)){
	//		cout<<" "<<i<<endl;
			int mae=i;
			int ato=l-mae;
			if(mae<ato){
				ans=min(ans,C[pp]+solve(c.substr(mae*2),1,n));
			}
			else{
				string tm=c.substr(0,l-2*ato);
				reverse(tm.begin(),tm.end());
				ans=min(ans,C[pp]+solve(tm,2,n));
			}
		}
	//	cout<<ans<<endl;
		pp++;
	}
	if( ans==inf*100000000ll)cout<<-1<<endl;
else	cout<<ans<<endl;
}

signed main(){
	
	cin.tie(0);
	ios::sync_with_stdio(false);
int n=1;
	//cin>>n;

	
	for(int i=0;i<n;i++)solve();
	
	return 0;
 }


Measured memory_bytes: 3764