#include <bits/stdc++.h>
using namespace std;
# include <stdio.h>
# include <math.h>

int main()
{

int ans=0;
int n;
  scanf("%d",&n);
  int temp;
map<int,int>arr;
for(int i=0;i<n;i++)
  {scanf("%d",&temp);
      arr[temp]++;
  }
 map<int,int>::iterator it=arr.begin();
while(it!=arr.end())
{ // it=arr.begin();
 int val=it->second;
 int key=it->first;
if(val%2==0)
    {  int k=val/2;
    it->second=it->second-val;
        arr[1+key]+=k;

       }
  else {  it->second=it->second-1;
        ans=ans+1; }


if(it->second<=0)
   it++;
}
cout<<ans<<endl;
}