#include <iostream>
#include <math.h>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <iomanip>
#include <set>
#include <bitset>
#include <unordered_map>
#define int long long
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using piii = tuple<int,int,int>;
#define f first
#define s second
#define endl '\n'
#define all(x) begin(x),end(x)
signed main(){
int n;cin >> n;
vector<pii> vc;
for(int i{};i < n;i++){
int a,b;cin >> a >> b;
vc.emplace_back(a,b);
}
sort(all(vc),greater<pii>());
int maxi = 0;
int cnt = 0;
for(auto [a,b]:vc){
if(maxi < b) maxi = b,cnt++;
}
cout << cnt;
}
