#include<bits/stdc++.h> using namespace std; int n; struct point { int l; int r; }; point v[110]; int sum; bool cmp(point x,point y) { return x.r<y.r; } int last; int main() { while(cin>>n) { if(!n) { return 0; } for(int i=1;i<=n;i++) { cin>>v[i].l; cin>>v[i].r; } sort(v+1,v+n+1,cmp); sum=0; last=0; for(int i=1;i<=n;i++) { if(v[i].l>=last) { cout<<v[i].l; cout<<" "; cout<<v[i].r; cout<<endl; sum++; last=v[i].r; } } cout<<sum; cout<<endl; } return 0; }