Problem:
Score: 500 points

Problem Statement

We have caught N sardines. The deliciousness and fragrantness of the i-th sardine is A_i and B_i, respectively.

We will choose one or more of these sardines and put them into a cooler. However, two sardines on bad terms cannot be chosen at the same time.

The i-th and j-th sardines (i \neq j) are on bad terms if and only if A_i \cdot A_j + B_i \cdot B_j = 0.

In how many ways can we choose the set of sardines to put into the cooler? Since the count can be enormous, print it modulo 1000000007.

Constraints

All values in input are integers.

1 \leq N \leq 2 \times 10^5

-10^{18} \leq A_i, B_i \leq 10^{18}

Input

Input is given from Standard Input in the following format:

N
A_1 B_1
:
A_N B_N

Output

Print the count modulo 1000000007.

Sample Input 1

3
1 2
-1 1
2 -1

Sample Output 1

5

There are five ways to choose the set of sardines, as follows:

The 1-st

The 1-st and 2-nd

The 2-nd

The 2-nd and 3-rd

The 3-rd

Sample Input 2

10
3 2
3 2
-1 1
2 -1
-3 -9
-8 12
7 7
8 1
8 2
8 4

Sample Output 2

479

Solution in Haskell (GHC 8.8.3) (judge verdict: Accepted)

{-# LANGUAGE TupleSections #-}

import qualified Data.ByteString.Char8 as B
import           Data.Maybe (fromJust)
import qualified Data.Map.Strict as M
import           Control.Monad (replicateM)

modT :: Integer
modT = 1000000007

main :: IO ()
main = do
  n <- getInt
  m <- M.fromListWith (+) . fmap ((, 1) . convert) <$> replicateM n getInts
  print . solve $ m

convert :: [Int] -> (Int, Int)
convert [a, b]
  | a == 0 && b == 0 = (0, 0)
  | a == 0 = (0, 1)
  | b == 0 = (1, 0)
  | otherwise = let gcd' = gcd a b
                in if b < 0
                   then (-div a gcd', -div b gcd')
                   else (div a gcd', div b gcd')

solve :: M.Map (Int, Int) Int -> Integer
solve map = let zero = M.findWithDefault 0 (0, 0) map
                ans = solve' . M.delete (0, 0) $ map
            in (fromIntegral zero + ans - 1) `mod` modT

solve' :: M.Map (Int, Int) Int -> Integer
solve' map = go 1 map
  where
    go :: Integer -> M.Map (Int, Int) Int -> Integer
    go acc map = if M.null map
                 then acc
                 else whenNotNull acc map

    whenNotNull :: Integer -> M.Map (Int, Int) Int -> Integer
    whenNotNull acc map =
      let ((a, b), count) = M.elemAt 0 map
          inv = if a > 0
                then (-b, a)
                else (b, -a)
          count' = M.findWithDefault 0 inv map
          ccount = ((2 ^ count `mod` modT) + (2 ^ count' `mod` modT) - 1)
            `mod` modT
          nacc = (ccount * acc) `mod` modT
      in nacc `seq` go nacc . M.delete (a, b) . M.delete inv $ map

getInt = fst . fromJust . B.readInt <$> B.getLine

getInts = fmap (fst . fromJust . B.readInt) . B.words <$> B.getLine