#include<iostream.h>
    int n;
    int nal[100];
    int mass[100][2];
    int del();
void main(){
    cin >> n;
    int j;
    for(int i=0;i<n;i++)
        nal[i]=0;
    for(i=0;i<n;i++)
        {
            cin >> mass[i][0];
            cin >> mass[i][1];
            if(mass[i][1]<mass[i][0])
                {
                    int t=mass[i][1];
                    mass[i][1]=mass[i][0];
                    mass[i][0]=t;
                }
        }
    for(i=0;i<n-1;i++)
        for(j=0;j<n-1;j++)
            if(mass[j][0]>mass[j+1][0])
                {
                    int t1=mass[j][0];
                    int t2=mass[j][1];
                    mass[j][0]=mass[j+1][0];
                    mass[j][1]=mass[j+1][1];
                    mass[j+1][0]=t1;
                    mass[j+1][1]=t2;
                }
    while(del());
    j=0;
    for(i=0;i<n;i++)
        if(nal[i]==0)
            j++;
    cout << j<<"\n";
    for(i=0;i<n;i++)
        if(nal[i]==0)
            cout<<mass[i][0]<<" "<<mass[i][1]<<"\n";
}
int del(){
    int quan=0;
    int nquan;
    int thr;
    for(int i=0;i<n;i++)
        if(nal[i]==0)
            {
                nquan=0;
                for(int j=0;j<n;j++)
                    if((nal[j]==0)&&(j!=i))
                        if(((mass[j][0]>=mass
[i][0])&&(mass[j][0]<mass[i][1]))
                        ||((mass[j][1]>mass[i]
[0])&&(mass[j][1]<=mass[i][1]))
                        ||((mass[j][0]<=mass
[i][0])&&(mass[j][1]>=mass[i][1])))
                            nquan++;
                if(nquan>quan)
                    {
                        quan=nquan;
                        thr=i;
                    }
            }
    if(quan!=0)
        {
            nal[thr]=1;
            return 1;
        }
    return 0;
}