#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool read(T &x) {
  int c = getchar();
  int sgn = 1;
  while (~c && c<'0' | c> '9') {
    if (c == '-') sgn = -1;
    c = getchar();
  }
  for (x = 0; ~c && '0' <= c && c <= '9'; c = getchar()) x = x * 10 + c - '0';
  x *= sgn;
  return ~c;
}
struct debugger {
  template <typename T>
  debugger &operator,(const T &v) {
    cerr << v << "    ";
    return *this;
  }
} dbg;
template <class T>
void __stl_print__(T &x) {
  cerr << "[";
  for (__typeof((x).end()) i = (x).begin(); i != (x).end(); ++i)
    cerr << (i != x.begin() ? ", " : "") << *i;
  cerr << "]" << endl;
}
template <class T, class U>
inline T max(T &a, U &b) {
  return a > b ? a : b;
}
template <class T, class U>
inline T min(T &a, U &b) {
  return a < b ? a : b;
}
template <class T, class U>
inline T swap(T &a, U &b) {
  T tmp = a;
  a = b;
  b = tmp;
}
const long long INF = (1ll) << 50;
const int mx = 1e5 + 7;
const int mod = 1000000007;
const double pi = 2 * acos(0.0);
int EQ(double d) {
  if (fabs(d) < 1e-7) return 0;
  return d > 1e-7 ? 1 : -1;
}
int arr[102];
bool flag[102];
int main() {
  int n = ({
    int a;
    read(a);
    a;
  });
  for (__typeof((n)-1) i = (0); i <= ((n)-1); ++i)
    arr[i] = ({
      int a;
      read(a);
      a;
    });
  sort(arr, arr + n);
  int cnt = 0;
  for (__typeof((n)-1) i = (0); i <= ((n)-1); ++i) {
    if (flag[i]) continue;
    flag[i] = 1;
    cnt++;
    int take = 1;
    for (__typeof(n - 1) j = (i + 1); j <= (n - 1); ++j) {
      if (!flag[j] && arr[j] >= take) {
        take++;
        flag[j] = 1;
      }
    }
  }
  cout << cnt << endl;
}
