local n = io.read("*n")

local parent = {}
for i = 1, 2 * n do parent[i] = i end

local function uf_findroot(idx)
  local idx_update = idx
  while parent[idx] ~= idx do
    idx = parent[idx]
  end
  while parent[idx_update] ~= idx do
    parent[idx_update], idx_update = idx, parent[idx_update]
  end
  return idx
end

local x, y = {}, {}
local xinvmap, yinvmap = {}, {}
local xary, yary = {}, {}
for i = 1, n do
  x[i], y[i] = io.read("*n", "*n")
  if not xinvmap[x[i]] then
    table.insert(xary, x[i])
    xinvmap[x[i]] = #xary
  end
  if not yinvmap[y[i]] then
    table.insert(yary, y[i])
    yinvmap[y[i]] = n + #yary
  end
end

for i = 1, n do
  local xi, yi = x[i], y[i]
  local idx1, idx2 = xinvmap[xi], yinvmap[yi]
  local p1, p2 = uf_findroot(idx1), uf_findroot(idx2)
  parent[p2], parent[idx2] = p1, p1
end
local groups = {}
for i = 1, 2 * n do
  local p = uf_findroot(i)
  if not groups[p] then
    groups[p] = {}
    groups[p].xcnt = 0
    groups[p].ycnt = 0
    groups[p].pointcnt = 0
  end
  if i <= n then
    groups[p].xcnt = groups[p].xcnt + 1
  else
    groups[p].ycnt = groups[p].ycnt + 1
  end
end
for i = 1, n do
  local xi, yi = x[i], y[i]
  local p = uf_findroot(xinvmap[xi])
  groups[p].pointcnt = groups[p].pointcnt + 1
end
local ret = 0
for k, v in pairs(groups) do
  if 1 < v.xcnt and 1 < v.ycnt then
    ret = ret + v.xcnt * v.ycnt - v.pointcnt
  end
end
print(ret)
