#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:2000000")
#pragma comment(linker, "/HEAP:2000000")
using namespace std;
void print_width(long long x) {
  std::cout << std::fixed;
  std::cout << std::setprecision(x);
}
long long power(long long x, long long y, long long p = 1000000007) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
void printArr(long long a[], long long n) {
  for (long long i = 0; i < n; i++) cout << a[i] << " ";
  cout << '\n';
}
void printVector(std::vector<long long> v) {
  for (long long i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << '\n';
}
void printVectorPair(std::vector<pair<long long, long long>> v) {
  for (long long i = 0; i < v.size(); i++)
    cout << v[i].first << " " << v[i].second << '\n';
  ;
  cout << '\n';
}
long long Min(long long a, long long b, long long c) {
  if (a < b and a < c) return a;
  if (b < c) return b;
  return c;
}
void initialize(long long arr[], long long n) {
  for (long long i = 0; i <= n; i++) arr[i] = i;
}
long long root(long long arr[], long long i) {
  while (arr[i] != i) {
    arr[i] = arr[arr[i]];
    i = arr[i];
  }
  return i;
}
void Union(long long arr[], long long a, long long b) {
  long long root_a = root(arr, a);
  long long root_b = root(arr, b);
  arr[root_a] = root_b;
}
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
long long power_wm(long long x, long long y) {
  long long res = 1;
  while (y > 0) {
    if (y & 1) res = (res * x);
    y = y >> 1;
    x = (x * x);
  }
  return res;
}
long double dpower(long double x, long long y) {
  long double res = 1;
  while (y > 0) {
    if (y & 1) res = (res * x);
    y = y >> 1;
    x = (x * x);
  }
  return res;
}
std::vector<long long> vsum(std::vector<long long> a) {
  std::vector<long long> s(a.size());
  s[0] = a[0];
  for (long long i = 1; i <= a.size() - 1; i++) {
    s[i] = s[i - 1] + a[i];
  }
  return s;
}
bool comp(pair<long long, long long> a, pair<long long, long long> b) {
  long long x = a.second * b.first;
  long long y = a.first * b.second;
  if (x <= y)
    return false;
  else
    return true;
}
bool is_cap(char a) {
  if (a <= 'Z' and a >= 'A')
    return true;
  else
    return false;
}
bool is_small(char a) {
  if (a <= 'z' and a >= 'a')
    return true;
  else
    return false;
}
string findSum(string str1, string str2) {
  string str = "";
  if (str1.size() > str2.size()) {
    swap(str1, str2);
  }
  int n1 = str1.size(), n2 = str2.size();
  reverse(str1.begin(), str1.end());
  reverse(str2.begin(), str2.end());
  int carry;
  carry = 0;
  for (int i = 0; i < n1; i++) {
    int sum;
    sum = ((str1[i] - '0') + (str2[i] - '0') + carry);
    str.push_back(sum % 10 + '0');
    carry = sum / 10;
  }
  for (int i = n1; i < n2; i++) {
    int sum;
    sum = ((str2[i] - '0') + carry);
    str.push_back(sum % 10 + '0');
    carry = sum / 10;
  }
  if (carry) str.push_back(carry + '0');
  reverse(str.begin(), str.end());
  return str;
}
bool mcomp(long long a, long long b, long long c, long long d) {
  if (a == b and b == c and c == d)
    return true;
  else
    return false;
}
vector<vector<long long>> g(200001, vector<long long>(0));
long long dfs(long long x, std::vector<long long> &vis,
              std::vector<long long> &dfs_seq,
              std::vector<long long> &children) {
  dfs_seq.push_back(x);
  for (long long i = 0; i < g[x].size(); i++) {
    long long y = g[x][i];
    if (vis[y] == 0) {
      vis[y] = 1;
      dfs(y, vis, dfs_seq, children);
      children[x] += 1 + children[y];
    }
  }
  return 0;
}
long long c2(long long n) { return (n * (n - 1)) / 2; }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n;
  cin >> n;
  std::vector<long long> a(n);
  for (long long i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end(), greater<long long>());
  ;
  for (long long b = 1; b <= n; b++) {
    vector<vector<long long>> g(b + 1, vector<long long>(0));
    ;
    long long p = 0;
    for (long long i = 0; i < n; i++) {
      g[p].push_back(a[i]);
      p = (p + 1) % b;
    }
    long long flag = 0;
    for (long long j = 0; j < b; j++) {
      for (long long i = 0; i < g[j].size(); i++) {
        if (g[j][i] >= (g[j].size() - (i + 1))) {
        } else {
          flag = 1;
        }
      }
    }
    if (flag == 0) {
      cout << b;
      return 0;
    }
  }
  return 0;
}
