io.input("test2")
io.input("input")

function pos2index( pos )
  return pos.x*10000 + pos.y
end

function constrain( n, min, max )
  -- returns converted n, and if it was converted
  local min = min or -1
  local max = max or 1
  if n < min then return min, true
  elseif n > max then return max, true
  else return n, false
  end
end

local head = { x=1, y=1 }
local n = 9
local tail = {}
for i=1,n do tail[i] = { x=1, y=1 } end
local visitedP1 = { [pos2index(tail[1])] = true }
local visitedP2 = { [pos2index(tail[n])] = true }
local resultP1 = 1
local resultP2 = 1

for line in io.lines() do
  local dir, q = string.match(line, "^(%a) (%d+)$")
  q = tonumber(q)
  for step = 1,q do
    if dir == "R" then
      head.x = head.x + 1
    elseif dir == "L" then
      head.x = head.x - 1
    elseif dir == "U" then
      head.y = head.y + 1
    elseif dir == "D" then
      head.y = head.y - 1
    end

    -- loop through tails
    for i=1,n do
      local h = head
      if i>1 then h = tail[i-1] end
      local t = tail[i]
      local dif = { x=h.x-t.x, y=h.y-t.y }
      -- gx, gy indicate if the abs diff was greater than 1
      local dx, gx = constrain(dif.x) 
      local dy, gy = constrain(dif.y) 
      if dif.x == 0 and gy then -- vertical
        t.y = t.y + dy
      elseif dif.y == 0 and gx then -- horizontal
        t.x = t.x + dx
      elseif gx or gy then -- diagonal further away
        t.y = t.y + dy
        t.x = t.x + dx
      end
    end

    -- part 1
    local index = pos2index(tail[1])
    if not visitedP1[index] then
      visitedP1[index] = true
      resultP1 = resultP1 + 1
    end
    -- part 2
    local index = pos2index(tail[n])
    if not visitedP2[index] then
      visitedP2[index] = true
      resultP2 = resultP2 + 1
    end
--    visitedP1[ pos2index(tail[1]) ] = true
--    visitedP2[ pos2index(tail[n]) ] = true
  end
end
print("part 1", resultP1)
print("part 2", resultP2)

local result = 0
for k, v in pairs(visitedP1) do
  result = result + 1
end
print("part 1", result, resultP1)

local result = 0
for k, v in pairs(visitedP2) do
  result = result + 1
end
print("part 2", result, resultP2)