#include <bits/stdc++.h>
using namespace std;
long long power(long long a, long long b) {
  long long result = 1;
  while (b > 0) {
    if (b % 2 == 1) {
      result *= a;
    }
    a *= a;
    b /= 2;
  }
  return result;
}
long long gcd(long long x, long long y) {
  long long r;
  while (y != 0 && (r = x % y) != 0) {
    x = y;
    y = r;
  }
  return y == 0 ? x : y;
}
long long countSetBits(long long x) {
  long long Count = 0;
  while (x > 0) {
    if (x & 1) Count++;
    x = x >> 1;
  }
  return Count;
}
bool isPerfectSquare(long long n) {
  long long sr = sqrt(n);
  if (sr * sr == n)
    return true;
  else
    return false;
}
long long mod(long long x, long long M) { return ((x % M + M) % M); }
long long add(long long a, long long b, long long M) {
  return mod(mod(a, M) + mod(b, M), M);
}
long long mul(long long a, long long b, long long M) {
  return mod(mod(a, M) * mod(b, M), M);
}
long long powerM(long long a, long long b, long long M) {
  long long res = 1;
  while (b) {
    if (b % 2 == 1) {
      res = mul(a, res, M);
    }
    a = mul(a, a, M);
    b /= 2;
  }
  return res;
}
long long modInverse(long long n, long long M) { return powerM(n, M - 2, M); }
long long nCrM(long long n, long long r, long long M) {
  if (n < r) return 0;
  if (r == 0) return 1;
  vector<long long> fact(n + 1);
  fact[0] = 1;
  for (long long i = 1; i <= n; i++) {
    fact[i] = mul(fact[i - 1], i, M);
  }
  return mul(mul(fact[n], modInverse(fact[r], M), M),
             modInverse(fact[n - r], M), M);
}
void solve() {
  long long n;
  cin >> n;
  vector<long long> v(n);
  for (auto& w : v) cin >> w;
  sort(v.begin(), v.end(), greater<int>());
  long long l = 1;
  long long r = n;
  while (l < r) {
    long long mid = (l + r) / 2;
    long long fal = 0;
    vector<vector<long long>> vv(mid);
    long long curr = 0;
    long long ans = n;
    while (curr < n) {
      for (long long i = 0; i < mid; i++) {
        if (curr < n) {
          vv[i].push_back(v[curr]);
          curr++;
        }
      }
    }
    for (long long i = 0; i < mid; i++) {
      long long curr = 0;
      for (long long j = vv[i].size() - 1; j >= 0; j--) {
        if (curr > vv[i][j]) {
          fal++;
          break;
        }
        curr++;
      }
    }
    if (fal != 0) {
      l = mid + 1;
    } else {
      ans = mid;
      r = mid;
    }
  }
  cout << l << '\n';
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  solve();
  return 0;
}
