local n = io.read("*n", "*l")
local b = {}
local m = {}
for i = 1, n do
  local str = io.read()
  local a = ""
  a, b[i] = str:match("(%w+) (%w+)")
  m[a] = true
end
for i = 1, n do
  if not m[b[i]] then
    m[b[i]] = true
    print(b[i])
  end
end