388A.cpp

//21171_somesh || asomesh999
//AC

#include<bits/stdc++.h>
using namespace std;
#define fr(i,a,b) for(long long i=a;i<b;i++)
#define io ios::sync_with_stdio(false);cin.tie(NULL);
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
long int mod=1000000007;

int main()
{
	io
	#ifdef SOMU
		clock_t startTime = clock();
		freopen("input.txt","r",stdin);
	#endif

	int n;
	cin >> n;
	vl arr(n);
	fr(i, 0, n) {
		cin >> arr[i];
	}
	sort(arr.begin(), arr.end());
	int piles = 0;
	int size = 0;
	int pos = 0;
	while(pos < n) {
		size = 0;
		fr(i, 0, n) {
			if(size <= arr[i]) {
				size++;
				arr[i] = -1;
				pos++;
			}
		}
		piles++;
	}
	cout << piles;

	#ifdef SOMU
		cerr << endl <<setprecision(20)<< double( clock() - startTime ) / (double)CLOCKS_PER_SEC<< " seconds." << endl;
	#endif
	return 0;
}