package main

import . "fmt"

const X=5e17

func abs(a int64) int64 {
	if a<0 {
		return -a
	}
	return a
}

func max(a,b int64) int64 {
	if a<b {
		return b
	}
	return a
}

func main() {
	var n int
	Scan(&n)
	a:=make([]int64,n,n)
	b:=make([]int64,n,n)
	for i:=range a {
		Scan(&a[i],&b[i])
	}
	u:=[]int{}
	v:=[]int{}
	for q:=0;q<50;q++ {
	f:=make([]bool,n+1,n+1)
	f[0]=true
	for i:=len(u);q>0&&i<50;i++ {
		best:=int64(X)*2
		t:=-1
		for k:=1;k<n;k++ {
			aa:=(a[0]+a[k])/2
			bb:=(b[0]+b[k])/2
			s:=max(abs(aa-X),abs(bb-X))
			if s<best {
				best=s
				t=k
			}
		}
		if t>0 {
			f[t]=true
			u=append(u,1)
			v=append(v,t+1)
			aa:=(a[0]+a[t])/2
			bb:=(b[0]+b[t])/2
			a[0],b[0]=aa,bb
			a[t],b[t]=aa,bb
			break
		} else {
			break
		}
	}
	for i:=len(u);i<50;i++ {
		best :=int64(X+X)
		t1,t2:=-1,-1
		for k:=range a {
			if f[k] {
				continue
			}
			for h:=range a {
				if k==h||f[h] {
					continue
				}
				aa:=(a[k]+a[h])/2
				bb:=(b[k]+b[h])/2
				s:=max(abs(aa-X),abs(bb-X))
				if s<best {
					best,t1,t2=s,k,h
				}
			}
		}
		if t1 <0 {
			break
		} else {
			u=append(u,t1+1)
			v=append(v,t2+1)
			aa:=(a[t1]+a[t2])/2
			bb:=(b[t1]+b[t2])/2
			a[t1],b[t1]=aa,bb
			a[t2],b[t2]=aa,bb
			break
		}
		
	}
	}
	Println(len(u))
	for i,e:=range u {
		Println(e,v[i])
	}
}