#include <iostream>
using namespace std;
struct Node {
int left, right;
int father;
}node[
1000];
bool Judge(
int a,
int b) {
if(node[b].left >= node[a].right || node[b].right <= node[a].left) {
return false;
}
else
return true;
}
void Union(
int a,
int b) {
int af = a;
int bf = b;
while(node[af].father != af)
af = node[af].father;
while(node[bf].father != bf)
bf = node[bf].father;
if(af<bf)
node[bf].father = af;
else if(af>bf)
node[af].father = bf;
}
int main() {
int n;
cin>>n;
for(
int i=
0;i<n;i++) {
cin>>node[i].left>>node[i].right;
node[i].father = i;
}
for(
int i=
0;i<n-
1;i++) {
for(
int j=i+
1;j<n;j++) {
if(Judge(i,j)) {
Union(i,j);
}
}
}
int sum =
0;
for(
int i=
0;i<n;i++) {
if(node[i].father == i) {
sum ++;
}
}
printf(
"sum is %d",sum);
return 0;
}
