class Digraph:
    """重み[なし]有向グラフを生成する.

    """

    #入力定義
    def __init__(self,vertex=[]):
        self.vertex=set(vertex)

        self.edge_number=0
        self.vertex_number=len(vertex)

        self.adjacent_out={v:set() for v in vertex} #出近傍(vが始点)
        self.adjacent_in={v:set() for v in vertex} #入近傍(vが終点)

    #頂点の追加
    def add_vertex(self,*adder):
        for v in adder:
            if not self.vertex_exist(v):
                self.adjacent_in[v]=set()
                self.adjacent_out[v]=set()

                self.vertex.add(v)
                self.vertex_number+=1

    #辺の追加
    def add_edge(self,From,To):
        self.add_vertex(From)
        self.add_vertex(To)

        if To not in self.adjacent_out[From]:
            self.adjacent_out[From].add(To)
            self.adjacent_in[To].add(From)
            self.edge_number+=1

    #辺を除く
    def remove_edge(self,From,To):
        self.add_vertex(From)
        self.add_vertex(To)

        if To in self.adjacent_out[From]:
            self.adjacent_out[From].discard(To)
            self.adjacent_in[To].discard(From)
            self.edge_number-=1

    #頂点を除く
    def remove_vertex(self,*vertexes):
        for  v in vertexes:
            if v in self.vertex:
                self.vertex_number-=1

                for u in self.adjacent_out[v]:
                    self.adjacent_in[u].discard(v)
                    self.edge_number-=1
                del self.adjacent_out[v]

                for u in self.adjacent_in[v]:
                    self.adjacent_out[u].discard(v)
                    self.edge_number-=1
                del self.adjacent_in[v]
                self.vertex.discard(v)

    #Walkの追加
    def add_walk(self,*walk):
        N=len(walk)
        for k in range(N-1):
            self.add_edge(walk[k],walk[k+1])

    #Cycleの追加
    def add_cycle(self,*cycle):
        self.add_walk(*cycle)
        self.add_edge(cycle[-1],cycle[0])

    #頂点の交換
    def __vertex_swap(self,p,q):
        self.vertex.sort()

    #グラフに頂点が存在するか否か
    def vertex_exist(self,v):
        return v in self.vertex

    #グラフに辺が存在するか否か
    def edge_exist(self,From,To):
        if self.vertex_exist(From) and self.vertex_exist(To):
            return False
        return To in self.adjacent_out[From]

    #近傍
    def neighbohood(self,v):
        """vの出近傍, 入近傍を出力する.

        Input:
        v:頂点

        Output:
        (出近傍, 入近傍)
        """
        if not self.vertex_exist(v):
            return (set(),set())
        return (self.adjacent_out[v],self.adjacent_in[v])

    #出次数
    def out_degree(self,v):
        if not self.vertex_exist(v):
            return 0
        return len(self.adjacent_out[v])

    #入次数
    def in_degree(self,v):
        if not self.vertex_exist(v):
            return 0
        return len(self.adjacent_in[v])

    #次数
    def degree(self,v):
        return (self.out_degree(v),self.in_degree(v))

    #頂点数
    def vertex_count(self):
        return self.vertex_number

    #辺数
    def edge_count(self):
        return self.edge_number

    #頂点vに到達可能な頂点
    def reachable_to(self,v):
        if not self.vertex_exist(v):
            return []

        from collections import deque
        T={v:0 for v in self.vertex}
        T[v]=1
        Q=deque([v])
        while Q:
            x=Q.popleft()
            for y in self.adjacent_in[x]:
                if not T[y]:
                    T[y]=1
                    Q.append(y)
        return [x for x in self.vertex if T[x]]

    #頂点vから到達可能な頂点
    def reachable_from(self,v):
        if not self.vertex_exist(v):
            return []

        from collections import deque
        T={v:0 for v in self.vertex}
        T[v]=1
        Q=deque([v])
        while Q:
            x=Q.popleft()
            for y in self.adjacent_out[x]:
                if not T[y]:
                    T[y]=1
                    Q.append(y)
        return [x for x in self.vertex if T[x]]

    #深いコピー
    def deepcopy(self):
        from copy import deepcopy
        D=Digraph()
        D.vertex=deepcopy(self.vertex)
        D.edge_number=self.edge_number
        D.vertex_number=len(self.vertex)
        D.adjacent_out=deepcopy(self.adjacent_out)
        D.adjacent_in=deepcopy(self.adjacent_in)
        return D

#Warshall–Floyd
def Warshall_Floyd(D):
    """Warshall–Floyd法を用いて,全点間距離を求める.

    D:負Cycleを含まない有向グラフ
    """
    T={v:{} for v in D.vertex} #T[u][v]:uからvへ
    for u in D.vertex:
        for v in D.vertex:
            if v==u:
                T[u][v]=0
            elif v in D.adjacent_out[u]:
                T[u][v]=1
            else:
                T[u][v]=float("inf")

    for u in D.vertex:
        for v in D.vertex:
            for w in D.vertex:
                T[v][w]=min(T[v][w],T[v][u]+T[u][w])

    return T

def Dijkstra(D,From,To,with_path=False):
    """Dijksta法を用いて,FromからToまでの距離を求める.

    D:辺の重みが全て非負の有向グラフ
    From:始点
    To:終点
    with_path:最短路も含めて出力するか?

    (出力の結果)
    with_path=True->(距離,最短経路の辿る際の前の頂点)
    with_path=False->距離
    """
    from copy import copy
    from heapq import heappush,heappop

    T={v:float("inf") for v in D.vertex}
    T[From]=0

    if with_path:
        Prev={v:None for v in D.vertex}

    Q=[(0,From)]

    Flag=False
    while Q:
        c,u=heappop(Q)

        if u==To:
            Flag=True
            break

        if T[u]<c:
            continue

        for v in D.adjacent_out[u]:
            if T[v]>T[u]+1:
                T[v]=T[u]+1
                heappush(Q,(T[v],v))

                if with_path:
                    Prev[v]=u

    if not Flag:
        if with_path:
            return (float("inf"),None)
        else:
            return float("inf")

    if with_path:
        path=[To]
        u=To
        while (Prev[u]!=None):
            u=Prev[u]
            path.append(u)
        return (T[To],path[::-1])
    else:
        return T[To]
#================================================
S=""
N=int(input())
A=[]
for _ in range(N):
    A.append(input())
    S+=A[-1]

M=int(input())
B=[]
for _ in range(M):
    B.append(input())

D=Digraph(S)
for alpha in A:
    for i in range(len(alpha)-1):
        D.add_edge(alpha[i],alpha[i+1])

for beta in B:
    for j in range(len(beta)-1):
        D.add_edge(beta[j],beta[j+1])

X=Warshall_Floyd(D)
flag=0
for s in S:
    for t in S:
        if X[s][t]==len(S)-1:
            flag+=1
            i,j=s,t

if flag!=1:
    print(-1)
    exit()

_,A=Dijkstra(D,i,j,True)
print("".join(A))