#include <bits/stdc++.h>   using namespace std;   int n, w[1000999];   int arr[1009999];   int main() {     scanf( %d , &n);     for (int i = 0; i < n; i++) {       scanf( %d , &w[i]);       arr[w[i]]++;     }     for (int i = 0; i < 1000099; i++) {       arr[i + 1] += arr[i] / 2;       arr[i] = arr[i] % 2;     }     int ans = 0;     for (int i = 0; i < 1000099; i++) {       if (arr[i] >= 1) {         ans++;       }     }     cout << ans << endl;   }   