A restaurant received n orders for the rental. Each rental order reserve the restaurant for a continuous period of time, the i-th order is characterized by two time values — the start time li and the finish time ri (li ≤ ri).

Restaurant management can accept and reject orders. What is the maximal number of orders the restaurant can accept?

No two accepted orders can intersect, i.e. they can't share even a moment of time. If one order ends in the moment other starts, they can't be accepted both.

Input

The first line contains integer number n (1 ≤ n ≤ 5·105) — number of orders. The following n lines contain integer values li and ri each (1 ≤ li ≤ ri ≤ 109).

Output

Print the maximal number of orders that can be accepted.

Examples

Input

2
7 11
4 7


Output

1


Input

5
1 2
2 3
3 4
4 5
5 6


Output

3


Input

6
4 8
1 5
4 7
2 5
1 3
6 8


Output

2
// see this : https://www.geeksforgeeks.org/activity-selection-problem-greedy-algo-1/
import java.util.*;
import java.io.*;
public class lp1{  
 
static class act implements Comparable<act>
{
    int l,r;
    act()
     {
       
     }
    public int compareTo(act p)
       {   return this.r-p.r;}
}

public static void main(String[] args){

int n = ni();
act p[] = new act[n];

for(int i=0;i<n;i++)
{
    p[i] = new act();
    p[i].l = ni();
    p[i].r = ni();
}  
   Arrays.sort(p);
 int ans=1,j=0;
 for(int i=1;i<n;i++)
  {
         if(p[i].l>p[j].r)
            {
                ans++;
                j=i;
             }
   }
 pn(ans);

   out.flush();
}
 
static class pair
	{
		int a,b;
		pair(){}
		pair(int c,int d){a=c;b=d;}
		@Override
		public int hashCode(){return (a+" "+b).hashCode();}
		@Override public boolean equals(Object c){if(a==((pair)c).a&&b==((pair)c).b)return true;return false;}
	}
static int get(int index)
        {
                return (index&(-index));
        }
static void add(int bit[],int index,int val)
        {
             while(index<bit.length)
               {
                    bit[index] = bit[index]+val;
                    index = index + get(index);
               }
        }
static int get(int bit[],int index)
         {
               int sum=0;
               while(index>0)
                {
                    sum = sum+bit[index];
                    index = index-get(index);
                }
              return sum;
         }
static void add(long bit[],int index,long val)
        {
             while(index<bit.length)
               {
                    bit[index] = bit[index]+val;
                    index = index + get(index);
               }
        }
static long get(long bit[],int index)
         {
               long sum=0;
               while(index>0)
                {
                    sum = sum+bit[index];
                    index = index-get(index);
                }
              return sum;
         }
static void compress(int a[])
         {      
                int n = a.length;
                Integer ar[] = new Integer[n];
                for(int i=0;i<n;i++)
                     ar[i] = a[i];
                Arrays.sort(ar);
                HashMap<Integer,Integer> hm = new HashMap();
                int st=1;
                for(int i=0;i<n;i++)
                    if(!hm.containsKey(ar[i]))
                        hm.put(ar[i],st++);
                for(int i=0;i<n;i++)
                   a[i] = hm.get(a[i]);
         }
static int find(int x,int p[]){ if(x==p[x]) return x; return p[x]=find(p[x],p) ;}
static void union(int x,int y,int p[]){ int xr=find(x,p),yr=find(y,p); if(xr!=yr){ p[xr]=yr;} }

static int abs(int x){ return x>0 ? x : -x; }
static long abs(long x){ return x>0 ? x : -x; }
static long gcd(long a,long b){ if(a==0)return b; if(b==0) return a;if(b%a==0) return a;return gcd(b%a,a); }
static int gcd(int a,int b){ if(a==0)return b; if(b==0) return a; if(b%a==0) return a;return gcd(b%a,a); }
static long min(long a,long b){ return a<b ? a : b; }
static int min(int a,int b){ return a<b ? a : b; }
static long max(long a,long b){ return a>b ? a : b; }
static int max(int a,int b){ return a>b ? a : b; }
static long pow(long a,long b,long md){ long ans=1;  while(b>0){if(b%2==1) ans = (ans*a)%md; a = (a*a)%md; b = b/2;} return ans; }
static int log2n(long a){ int te=0; while(a>0) {a>>=1; ++te; } return te; }


static void subtract_1(char s[]){if(s[0]=='0') return;int n = s.length,i=n-1;while(s[i]=='0')i--;s[i] =(char)((int)(s[i]-'0') + 47);for(int j=i+1;j<n;j++)s[j]='9';}
static void reverse(char s[]){int i1=0,i2=s.length-1; while(i1<i2){char t=s[i1];s[i1]=s[i2];s[i2]=t; i1++;i2--;} }
static String reverse(String r){String s = "";int i= r.length()-1; while(i>=0){ s=s+r.charAt(i);i--;}return s;}
static boolean pal(char s[]){ int i1=0,i2=s.length-1; while(i1<i2){ if(s[i1]!=s[i2]) return false; i1++;i2--;} return true;}
static boolean pal(String s){int n = s.length(),i1=0,i2=n-1;while(i1<i2){if(s.charAt(i1)!=s.charAt(i2))return false;i1++; i2--;}return true;}

// Input OutPut Functions
static PrintWriter out = new PrintWriter(System.out);
static FastReader sc=new FastReader();
static int ni(){ int x = sc.nextInt();return(x); }
static long nl(){ long x = sc.nextLong(); return(x); }
static String n(){ String str = sc.next(); return(str); }
static String ns(){ String str = sc.nextLine(); return(str);}
static double nd(){double d = sc.nextDouble(); return(d); }
static int[] ai(int n){ int a[] = new int[n]; for(int i=0;i<n;i++) a[i] = ni(); return a; }
static long[] al(int n) {long a[] = new long[n]; for(int i=0;i<n;i++) a[i] = nl(); return a; }
static double[] ad(int n) { double a[]= new double[n]; for(int i=0;i<n;i++) a[i]=nd(); return a;} 
static void p(Object o){ out.print(o); }
static void pn(Object o){ out.println(o); } 
 
static class FastReader{ 
BufferedReader br; 
StringTokenizer st;   
public FastReader() { br = new BufferedReader(new InputStreamReader(System.in));  }   
String next(){while(st==null || !st.hasMoreElements()){try{st = new StringTokenizer(br.readLine());}catch (IOException  e){e.printStackTrace();}}return st.nextToken();} 
int nextInt(){ return Integer.parseInt(next()); } 
long nextLong(){ return Long.parseLong(next()); } 
double nextDouble(){return Double.parseDouble(next()); } 
String nextLine(){ String str = ""; try{ str = br.readLine();} catch (IOException e){ e.printStackTrace();} return str;} 
  } 
}