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
{
{
// your code goes here
int n
= Integer.
parseInt(br.
readLine().
trim()); String temp
[] = br.
readLine().
trim().
split(" "); int arr[] = new int[n];
for(int i
= 0 ; i
<n
; i
++) arr
[i
]=Integer.
parseInt(temp
[i
]); int cnt[] = new int[1000100];
for(int i = 0 ; i< n;i++) cnt[arr[i]]++;
int ans=0;
for(int i = 0 ; i< 1000099; i++){
if(cnt[i]%2==0){
cnt[i+1]+=cnt[i]/2;
cnt[i]=0;
}
else{
cnt[i+1]+=cnt[i]/2;
cnt[i]=1;
ans++;
}
}
pw.print(ans);
pw.flush();
}
}
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