class Dijkstra():
    class Edge():
        def __init__(self, _to, _cost):
            self.to = _to
            self.cost = _cost

    def __init__(self, V):
        self.G = [[] for i in range(V)]
        self._E = 0
        self._V = V

    @property
    def E(self):
        return self._E

    @property
    def V(self):
        return self._V

    def add(self, _from, _to, _cost):
        self.G[_from].append(self.Edge(_to, _cost))
        self._E += 1

    def shortest_path(self, start):
        import heapq
        que = []
        d = [float("inf")] * self.V

        for s in start:
            d[s]=0
            heapq.heappush(que, (0, s))

        while len(que) != 0:
            cost, v = heapq.heappop(que)
            if d[v] < cost: continue

            for i in range(len(self.G[v])):
                e = self.G[v][i]
                if d[e.to] > d[v] + e.cost:
                    d[e.to] = d[v] + e.cost
                    heapq.heappush(que, (d[e.to], e.to))
        return d

N=int(input())
string=[]
for i in range(N):
    s,c=input().split()
    string.append((s,int(c)))

node=[(0,""),(1,"")]
for s,c in string:
    for j in range(len(s)):
        node.append((0,s[j:]))
    for j in range(len(s)-1,-1,-1):
        node.append((1,s[:j+1]))

node=list(set(node))

iddata={i:e for e,i in enumerate(node)}
n=len(iddata)
edge=[[] for i in range(n)]
for i in range(n):
    if node[i][0]==0:
        S=node[i][1]
        for s,c in string:
            if len(s)<=len(S):
                check=all(S[j]==s[-j-1] for j in range(len(s)))
                if check:
                    if len(s)==len(S):
                        next_node=(0,"")
                    else:
                        next_node=(0,S[len(s):])
                    next_id=iddata[next_node]
                    edge[i].append((next_id,c))
            else:
                check=all(S[j]==s[-j-1] for j in range(len(S)))
                if check:
                    if len(s)==len(S):
                        next_node=(1,"")
                    else:
                        next_node=(1,s[:len(s)-len(S)])
                    next_id=iddata[next_node]
                    edge[i].append((next_id,c))
    else:
        S=node[i][1]
        for s,c in string:
            if len(s)<=len(S):
                check=all(s[j]==S[-j-1] for j in range(len(s)))
                if check:
                    if len(s)==len(S):
                        next_node=(1,"")
                    else:
                        next_node=(1,S[:len(S)-len(s)])
                    next_id=iddata[next_node]
                    edge[i].append((next_id,c))
            else:
                check=all(s[j]==S[-j-1] for j in range(len(S)))
                if check:
                    if len(s)==len(S):
                        next_node=(0,"")
                    else:
                        next_node=(0,s[len(S):])
                    next_id=iddata[next_node]
                    edge[i].append((next_id,c))

palindrome=Dijkstra(n+1)
for i in range(n):
    for j,c in edge[i]:
        palindrome.add(j,i,c)

start=[]
for i in range(n):
    s=node[i][1]
    if len(s)==0:
        start.append(i)
    else:
        check=all(s[j]==s[-1-j] for j in range(len(s)))
        if check:
            start.append(i)

for s,c in string:
    id=iddata[0,s]
    palindrome.add(id,n,c)
    id=iddata[1,s]
    palindrome.add(id,n,c)

res=palindrome.shortest_path(start)
ans=res[n]

#print(list(map(lambda x:node[x],start)))
#for i in range(n):
    #if node[i][1]=="abc":
        #print(node[i])
        #print(list(map(lambda x:(node[x[0]],x[1]),edge[i])))

if ans!=float("inf"):
    print(ans)
else:
    print(-1)


Measured memory_bytes: 71576