A.cpp

#include <bits/stdc++.h>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define EACH(it,a) for(__typeof(a.begin()) it = a.begin(); it != a.end(); ++it)

#define DEBUG(x) { cout << #x << " = "; cout << (x) << endl; }
#define PR(a,n) { cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl; }
#define PR0(a,n) { cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl; }

#define sqr(x) ((x) * (x))
#define ll long long
#define SZ(X) ((int) ((X).size()))
using namespace std;

const int MN = 1000111;

int a[MN], n;

int main() {
    ios :: sync_with_stdio(false);
    while (scanf("%d", &n) == 1) {
        multiset<ll> all;
        FOR(i,1,n) {
            scanf("%d", &a[i]);
            all.insert(a[i]);
        }
        int res = 0;
        while (!all.empty()) {
            int u = *all.begin(); all.erase(all.begin());
            if (all.empty()) {
                ++res;
                break;
            }
            int v = *all.begin(); all.erase(all.begin());

            if (u == v) {
                all.insert(u + 1);
            }
            else {
                ++res;
                all.insert(v);
            }
        }
        cout << res << endl;
    }
}