#include <bits/stdc++.h>
#define int long long
#define endl "\n"
#define pb push_back
#define INF 1234567890
#define MOD 1000000007
#define PI atan(1)/4
#define mp make_pair
#define REP(i,n) for (int i = 0; i < n; i++)
#define FOR(i,a,b) for (int i = a; i <=b; i++)
#define REPD(i,n) for (int i = n-1; i >= 0; i--)
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define F first
#define S second
#define mii map<int,int>
#define vi vector<int>
#define vvi vector<vi>
#define itr :: iterator it
#define WL(t) while(t --)
#define gcd(a,b) __gcd((a),(b))
#define lcm(a,b) ((a)*(b))/gcd((a),(b))
#define print(x) cout << x << "\n";
#define debug(x) cout << x << "\n";
#define debug2(x,y) cout << x << " " << y << "\n";
#define debug3(x,y,z) cout << x << " " << y << " " << z << "\n";
#define debug4(x,y,z,zz) cout << x << " " << y << " " << z <<" "<<zz << "\n";
#define debug5(x,y,z,zz,yy) cout << x << " " << y << " " << z <<" "<<zz << " "<< yy << "\n";
#define ONLINE_JUDGE 54
/* AUTHOR : Jagreet 'v01d' Das Gupta */
using namespace std;
void solve();
signed main()
{
#ifndef ONLINE_JUDGE
freopen("../input.txt","r",stdin);
freopen("../output.txt","w",stdout);
#else
ios_base::sync_with_stdio(false);
cin.tie(NULL);
#endif
int t = 1;
//cin >> t;
WL(t) solve();
}
void solve()
{
int n;
cin >> n;
pii intervals[n];
REP(i,n) cin >> intervals[i].S >> intervals[i].F;
sort(intervals,intervals+n);
set<int> added;
REP(i,n)
{
bool exist = false;
int a = intervals[i].S;
int b = intervals[i].F;
auto ii = lower_bound(all(added),a);
auto jj = lower_bound(all(added),b);
for(auto it = ii;it!=jj;it++)
{
int x = *it;
if(x>=a&&x<=b)
{
exist = true;
break;
}
}
if(!exist)
{
added.insert(b);
}
}
print(added.size());
}
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