package main

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

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	cc := make([]circle, n)
	for i := 0; i < n; i++ {
		cc[i].x = getNextInt(scanner)
		cc[i].y = getNextInt(scanner)
	}
	dd := make([][3]int, 0, n*n)
	for i := 0; i < n; i++ {
		for j := 0; j < i; j++ {
			dd = append(dd, [3]int{i, j, dist(cc[i], cc[j])})
		}
	}
	removed := make([]bool, n)
	broken := make([]bool, n)
	sort.Slice(dd, func(i, j int) bool {
		return dd[i][2] < dd[j][2]
	})
	for i := 0; i < len(dd); i++ {
		if dd[i][0] == 0 {
			if removed[dd[i][1]] || broken[dd[i][1]] {
				continue
			}
			removed[dd[i][1]] = true
			continue
		}
		if dd[i][1] == 0 {
			if removed[dd[i][0]] || broken[dd[i][0]] {
				continue
			}
			removed[dd[i][0]] = true
			continue
		}
		if broken[dd[i][0]] || broken[dd[i][1]] {
			continue
		}
		if removed[dd[i][0]] || removed[dd[i][1]] {
			continue
		}
		broken[dd[i][0]] = true
		broken[dd[i][1]] = true
	}
	var ans int
	for i := 0; i < n; i++ {
		if removed[i] {
			ans++
		}
	}
	fmt.Fprintln(writer, ans)
}

type circle struct {
	x, y int
}

func dist(a, b circle) int {
	return (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y)
}