#include<algorithm> #include<string.h> #include<iostream> #include<stdio.h> #include<string.h> using namespace std; struct TvShow { int Ti_s; int Ti_e; bool operator <(const TvShow &A)const { return Ti_e < A.Ti_e; } }buf[1000]; int main() { int n; while (cin >> n) { if (n == 0) break; for (int i = 0; i < n; i++) { cin >> buf[i].Ti_s >> buf[i].Ti_e; } sort(buf, buf + n); int count = 0; int currentTime = 0; for (int i = 0; i < n; i++) { if (currentTime <= buf[i].Ti_s) { currentTime = buf[i].Ti_e; count++; } } cout << count << endl; } return 0; }