#include <bits/stdc++.h>
using namespace std;
void in() { return; }
template <typename T, typename... Types>
void in(T &a, Types &...b) {
  cin >> (a);
  in(b...);
}
void o() { return; }
template <typename T, typename... Types>
void o(T a, Types... b) {
  cout << (a);
  cout << ' ';
  o(b...);
}
bool sortin(const pair<long long int, long long int> &e,
            const pair<long long int, long long int> &f) {
  return (e.first < f.first);
}
bool POT(long long int x) { return x && (!(x & (x - 1))); }
long long int i, j, k, l, m, n, p, q, r, a, b, c, x, y, z, ts, mn = 1e18,
                                                               mod = 1e9 + 7;
long long int ar[1010002], br[1010002], xr[1010002], tem[1010002];
int main() {
  {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
  };
  in(n);
  for (long long int i = 0; i <= n - 1; i++) in(ar[i]), xr[ar[i]]++;
  for (long long int i = 0; i <= 1010000; i++) {
    xr[i + 1] += xr[i] / 2;
    if (xr[i] % 2) c++;
  }
  o(c);
}
