package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var wr = bufio.NewWriter(os.Stdout)

func out(x ...interface{}) {
	fmt.Fprintln(wr, x...)
}

func getI() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func getF() float64 {
	sc.Scan()
	i, e := strconv.ParseFloat(sc.Text(), 64)
	if e != nil {
		panic(e)
	}
	return i
}

func getInts(N int) []int {
	ret := make([]int, N)
	for i := 0; i < N; i++ {
		ret[i] = getI()
	}
	return ret
}

func getS() string {
	sc.Scan()
	return sc.Text()
}

// min, max, asub, absなど基本関数
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func asub(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func lowerBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] >= x
	})
	return idx
}

func upperBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] > x
	})
	return idx
}

type pos struct {
	x, y, idx int
}

func calcD(a, b pos) int {
	dx := a.x - b.x
	dy := a.y - b.y
	return dx*dx + dy*dy
}

func main() {
	defer wr.Flush()
	sc.Split(bufio.ScanWords)
	sc.Buffer([]byte{}, 1000000)
	// this template is new version.
	// use getI(), getS(), getInts(), getF()
	N := getI()
	x := make([]int, N)
	y := make([]int, N)

	for i := 0; i < N; i++ {
		x[i], y[i] = getI(), getI()
	}

	K := (N + 89) / 90
	for a := 0; a <= 8; a++ {
		for b := 0; b <= 9; b++ {
			ans := make([]int, 0)
			for i := 0; i < N; i++ {
				if x[i]%18 == a%18 && y[i]%10 == b%10 {
					ans = append(ans, i)
					continue
				}
				if x[i]%18 == (a+9)%18 && y[i]%10 == (b+5)%10 {
					ans = append(ans, i)
					continue
				}
			}
			if len(ans) >= K {
				out(len(ans))
				for _, e := range ans {
					fmt.Fprint(wr, e+1, " ")
				}
				out()
				return
			}
		}
	}
}