#include<bits/stdc++.h>
using namespace std;
int a[105],n,x,ans=0;
int main ()
{
	cin>>n;
	for (int i=1; i<=n; i++)
	{
		cin>>x;
		a[x]++;
	}
	for (int i=0; i<=100; i++)
	{
		ans+=a[i]%2;
		a[i+1]+=a[i]/2;
	}
	cout<<ans<<endl ;
	return 0;
}