1 #include<cstdio>
2 #include<algorithm>
3 #include<cstring>
4 using namespace std;
5 struct node
6 {
7 int st;
8 int ed;
9 };
10 node a[110];
11 int n,ans;
12 bool cmp(node x,node y)
13 {
14 if (x.ed==y.ed) return x.st<y.st;
15 return x.ed<y.ed;
16 }
17 int main()
18 {
19 scanf("%d",&n);
20 while (n!=0)
21 {
22 memset(a,0,sizeof(a));
23 for (int i=1;i<=n;i++) scanf("%d%d",&a[i].st,&a[i].ed);
24 sort(a+1,a+n+1,cmp);
25 //for (int i=1;i<=n;i++) printf("%d %d\n",i,a[i].ed);
26 ans=0;
27 int last=0;
28 for (int i=1;i<=n;i++)
29 if (a[i].st>=last)
30 {
31 ans++;
32 last=a[i].ed;
33 }
34 printf("%d\n",ans);
35 scanf("%d",&n);
36 }
37 return 0;
38 }