#include <iostream> #include <algorithm> using namespace std; struct q { int l, r; }a[110]; bool cmp(q a, q b) {return a.r < b.r;} int main() { int n, len = -1; cin >> n; while(n) { for(int i = 1; i <= n; i++) cin >> a[i].l >> a[i].r; sort(a + 1, a + n + 1, cmp); int cnt = 1, c = a[1].r; for(int i = 2; i <= n; i++) { if(a[i].l >= c) { cnt++; c = a[i].r; } } cout << cnt << endl; cin >> n; } return 0; }