def f(a, b)

  cnt = 0
  r = ""
  a.each_with_index{|aa, i|
    used_a = [false] * A.size
    used_b = [false] * B.size
    g = lambda{|a, b|
      # p [a, b]
      # p [used_a, used_b]
      if used_a.all?{|v|v} && used_b.all?{|v|v}
        return a == b && a
      end
      if a.size > b.size
        B.each_with_index{|bb, i|
          next if used_b[i]
          new_b = b + bb
          len = [new_b.size, a.size].min
          if new_b[0...len] == a[0...len]
            used_b[i] = true
            r = g.(a, new_b)
            return r if r
            used_b[i] = false
          end
        }
      else
        A.each_with_index{|aa, i|
          next if used_a[i]
          new_a = a + aa
          len = [new_a.size, b.size].min
          if new_a[0...len] == b[0...len]
            used_a[i] = true
            r = g.(new_a, b)
            return r if r
            used_a[i] = false
          end
        }
      end
      false
    }
    used_a[i] = true
    if r = g.(aa, "")
      cnt += 1
    end
    return false if cnt > 1
  }
  r
end

N = gets.to_i
A = N.times.map{gets.chomp}
M = gets.to_i
B = M.times.map{gets.chomp}

r = f(A, B)
puts r ? r : -1