/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String [] Args)
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int [] w  = new int[n];
        int [] b = new int[1000000+(int)Math.log(1000000)];
 
        for (int i=0; i<n; i++)
        {
            w[i]=sc.nextInt();
            b[w[i]]++;
        }
 
        int ans=0;
        for (int i = 0; i<b.length-1; i++)
        {
            if (b[i]>0){
            b[i+1]+=b[i]/2;
            b[i]=b[i]%2;
            ans+=b[i];
            }
        }
 
        System.out.print(ans);
    }
}

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