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#include <algorithm>
#include <iostream>
//#include <pair>
using namespace std;

int N;
pair<int, int> tab[500001];
int maxx = 0, x;

bool check(pair<int, int> a, pair<int, int> b) {
  if (a.second > b.second)
	return true;
  return false;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  cin >> N;
  for (int i = 0; i < N; ++i) {
	cin >> x;
	if(x > maxx) maxx = x;
	if (tab[x].second == 0) {
	  tab[x] = {x, 1};
	} else {
	  tab[x].second += 1;
	}
  }

  sort(tab, tab + maxx+1, check);
  int counter = 0;
	if(tab[0].second == 1){
		for (int i = 0; i < maxx; ++i) {
			if(tab[i].second == 0){
				break;
			}
			counter++;
		}
	}
	else{
	  int max1, index = maxx;
	  for (int i = 0; i < maxx; ++i) {
		if(tab[i].second == 0){
			break;
		}
		counter++;
		max1 = tab[i].second - 1;
		for (index; index > i; --index) {
			if(tab[index].second == 0) continue;
		  if (tab[index].second < max1) {
			max1 -= tab[index].second;
			tab[index].second = 0;
		  } 
		  else {
			tab[index].second -= max1;
			break;
		  }
		}
	  }
	}

  cout << counter;

  return 0;
}