local mfl, mce = math.floor, math.ceil
local n, k, p = io.read("*n", "*n", "*n")
local a, b = {}, {}
for i = 1, n do
  a[i] = io.read("*n")
end
for i = 1, n do
  b[i] = io.read("*n")
end

table.sort(a)
table.sort(b)

local function solve(x)
  local c1 = 0
  local apos = n
  for i = 1, n do
    while 0 < apos and x < a[apos] + b[i] do
      apos = apos - 1
    end
    if apos == 0 then break end
    c1 = c1 + apos
  end
  apos = n
  local c2 = 0
  for i = 1, n do
    while 0 < apos and p - 1 < a[apos] + b[i] do
      apos = apos - 1
    end
    if apos == 0 then break end
    c2 = c2 + apos
  end
  apos = n
  local c3 = 0
  for i = 1, n do
    while 0 < apos and p + x < a[apos] + b[i] do
      apos = apos - 1
    end
    if apos == 0 then break end
    c3 = c3 + apos
  end
  return k <= c3 - c2 + c1
end
local min, max = -1, p - 1
while 1 < max - min do
  local mid = mfl((min + max) / 2)
  if solve(mid) then
    max = mid
  else
    min = mid
  end
end
print(max)