function readline()
	local x1 = io.read("*n")
	io.read(1) -- ","
	local y1 = io.read("*n")
	io.read(4) -- " -> "
	local x2 = io.read("*n")
	io.read(1) -- ","
	local y2 = io.read("*n")
	io.read("*l") -- "...\n"
	return x1, y1, x2, y2
end

function mark(field, x, y, count, dx, dy)
	local i = 0
	while i <= count do
		local row = field[x+i*dx] or {}
		row[y+i*dy] = (row[y+i*dy] or 0) + 1
		field[x+i*dx] = row
		i = i + 1
	end
end

io.input(arg[3])
local x1, y1, x2, y2 = readline()
local field = {}
while x1 ~= nil do
	local x, y, count, dx, dy
	if x1 == x2 then
		mark(field, x1, math.min(y1, y2), math.abs(y1 - y2), 0, 1)
	elseif y1 == y2 then
		mark(field, math.min(x1, x2), y1, math.abs(x2 - x1), 1, 0)
	elseif x1 + y1 == x2 + y2 then
		mark(field, math.min(x1, x2), math.max(y1, y2), math.abs(x1 - x2), 1, -1)
	else
		mark(field, math.min(x1, x2), math.min(y1, y2), math.abs(x1 - x2), 1, 1)
	end
	x1, y1, x2, y2 = readline()
end

local count = 0
for r, row in pairs(field) do
	for c, col in pairs(row) do
		if col >= 2 then
			count = count + 1
		end
	end
end
print(count)