local bls, brs = bit.lshift, bit.rshift
local n = io.read("*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n")
end
local m = io.read("*n")
local b = {}
for i = 1, m do
  b[i] = io.read("*n")
end
table.sort(b, function(x, y) return x > y end)
local tot = bls(1, n)
local box_index, box_offset = {}, {}
local stagetask = {}
for i = 1, n do
  stagetask[i] = {}
end
for i = 1, tot - 1 do
  -- set empty state
  box_index[i] = 11
  box_offset[i] = 0
end
for i = 1, tot - 1 do
  local ti = i
  local cnt = 0
  for j = 1, n do
    if ti % 2 == 1 then
      cnt = cnt + 1
      ti = ti - 1
    end
    ti = ti / 2
  end
  table.insert(stagetask[cnt], i)
end
-- set first state
do
  local tmp = 1
  for i = 1, n do
    if a[i] <= b[1] then
      box_index[tmp] = 1
      box_offset[tmp] = a[i]
    end
    tmp = tmp * 2
  end
end

for stage = 1, n - 1 do
  local stlen = #stagetask[stage]
  for i_stagetask = 1, stlen do
    local used = stagetask[stage][i_stagetask]
    local bi = box_index[used]
    if bi <= m then
      local mul = 1
      local tmp = used
      for j = 1, n do
        if tmp % 2 == 0 then
          if box_offset[used] + a[j] <= b[bi] then
            if bi < box_index[used + mul] then
              box_index[used + mul] = bi
              box_offset[used + mul] = box_offset[used] + a[j]
            elseif bi == box_index[used + mul]
            and box_offset[used] + a[j] < box_offset[used + mul] then
              box_offset[used + mul] = box_offset[used] + a[j]
            end
          elseif bi ~= m and a[j] <= b[bi + 1] then
            if bi + 1 < box_index[used + mul] then
              box_index[used + mul] = bi + 1
              box_offset[used + mul] = a[j]
            elseif bi + 1 == box_index[used + mul]
            and a[j] < box_offset[used + mul] then
              box_offset[used + mul] = a[j]
            end
          end
        else
          tmp = tmp - 1
        end
        tmp = tmp / 2
        mul = mul * 2
      end
    end
  end
end

print(box_index[tot - 1] <= m and box_index[tot - 1] or -1)