local mfl = math.floor

local function comp(a, b)
  return a < b
end

local function lower_bound(ary, x)
  local num = #ary
  if num == 0 then return 1 end
  if not comp(ary[1], x) then return 1 end
  if comp(ary[num], x) then return num + 1 end
  local min, max = 1, num
  while 1 < max - min do
    local mid = mfl((min + max) / 2)
    if comp(ary[mid], x) then
      min = mid
    else
      max = mid
    end
  end
  return max
end

local n, q = io.read("*n", "*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n")
end
local b = {}
for i = 1, n do
  for j = 1, a[i] do
    table.insert(b, j)
  end
end
-- print(table.concat(b, " "))
local bsum = {b[1]}
for i = 2, #b do
  bsum[i] = bsum[i - 1] + b[i]
end

for iq = 1, q do
  local z = io.read("*n")
  local lb = lower_bound(bsum, z)
  if #bsum < lb then
    print(-1)
  else
    print(lb)
  end
end