#include<cstdio> #include<algorithm> using namespace std; struct ndu{ int x; int y; }I[110]; bool nidu(ndu a,ndu b){ if(a.x!=b.x) return a.x>b.x; else return a.y<b.y; } int main() { int n; while(scanf("%d",&n)!=EOF) { if(n==0) break; for(int i=0;i<n;i++) { scanf("%d%d",&I[i].x,&I[i].y); } sort(I,I+n,nidu); int ans=1; int last=I[0].x; for(int i=1;i<n;i++){ if(I[i].y<=last){ last=I[i].x; ans++; } } printf("%d\n",ans); } return 0; }