--https://www.lua.org/pil/11.4.html
local List = {}
function List.new ()
  return {first = 0, last = -1}
end

function List.pushleft (list, value)
  local first = list.first - 1
  list.first = first
  list[first] = value
end

function List.pushright (list, value)
  local last = list.last + 1
  list.last = last
  list[last] = value
end

function List.popleft (list)
  local first = list.first
  if first > list.last then return false end
  local value = list[first]
  list[first] = nil
  list.first = first + 1
  return value
end

function List.popright (list)
  local last = list.last
  if list.first > last then return false end
  local value = list[last]
  list[last] = nil
  list.last = last - 1
  return value
end

----------

local k=io.read("n")

local que=List.new()
for i=1,9 do
    List.pushright(que,i)
end

for i=1,k-1 do
    local pop=List.popleft(que)
    for j=-1,1 do
        local add=(pop%10)+j
        if 0<=add and add<=9 then
            List.pushright(que,pop*10+add)
        end
    end
end
print(List.popleft(que))