import java.util.*;
public class Cover implements Comparator{
   public int compare(Object o1,Object o2){
    Cover oo1 = (Cover)o1;
    Cover oo2 = (Cover)o2;

           if(oo1.q>oo2.q)
        return 1;
    else if(oo1.q>oo2.q)
        return -1;
    else
        return 0;

   }

    int q,z;
    public static void main(String[] args) {
        int n,i,j,k,l,a[],b[],ct=0,min=Integer.MAX_VALUE,pos=0;
        int tmp;
        Cover obj = new Cover();
        ArrayList<Cover> map = new ArrayList<Cover>();
        boolean visit[][];
        Scanner input = new Scanner(System.in);
        n = input.nextInt();
        a = new int[n];
        b = new int[n];
        visit = new boolean[n][n];
        for(i=0;i<n;i++)
        java.util.Arrays.fill(visit[i],true);

        for(i=0;i<n;i++){
        a[i] = input.nextInt();
        b[i] = input.nextInt();
        if(a[i]>b[i])
        {
        tmp = a[i];
        a[i] = b[i];
        b[i] = tmp;
        }
        }
        for(k=0;k<n;k++){ct=0;
        for(i=k,l=0;l<n;l++,i++){

        if(i>=n)i = i%n;
        if(visit[k][i]!=false){
        for(j=0;j<n;j++){

        if(i!=j)
        if(!(((a[j]<=a[i])&&(b[j]<=a[i]))||((a[j]>=b[i])&&(b[j])>=b[i]))){
        if(visit[k][j]!=false){
        visit[k][j]=false;
        ct++;
        }
        }}}}
        if(ct<min){
        min = ct;
        pos = k;

        }
        }


       System.out.println(n-min);


    for(i=0;i<n;i++){
    if(visit[pos][i]!=false)
    {
    obj = new Cover();
    obj.q = a[i];obj.z = b[i];
     map.add(obj);
    }

 }

Collections.sort(map,new Cover());

 ListIterator it = map.listIterator();
while(it.hasNext()){
obj = (Cover) it.next();
System.out.println(obj);

}
}
public String toString(){
return q + " " + z;
}
}