#include <bits/stdc++.h> using namespace std; pair<int ,int> a[105]; bool cmp(pair<int ,int>s1,pair<int,int>&s2){ return s1.second<s2.second; } int main(){ int n; cin>>n; while(n!=0){ cin>>n; for(int i = 1;i<=n;i++){ cin>>a[i].first>>a[i].second; } sort(a+1,a+n+1,cmp); int tmp = a[1].second,cnt = 1; for(int i = 2;i<=n;i++){ if(a[i].first>tmp){ cnt++; tmp = a[i].second; } } cout<<cnt<<endl; cin>>n; } }