#include <bits/stdc++.h>
using namespace std;
using namespace std;
long long int gcd(long long int a, long long int b) {
  if (b == 0) return a;
  a %= b;
  return gcd(b, a);
}
long long int exte_gcd(long long int a, long long int b, long long int& x,
                       long long int& y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  long long int x1, y1;
  long long int d = exte_gcd(b, a % b, x1, y1);
  x = y1;
  y = x1 - y1 * (a / b);
  return d;
}
long long int powe(long long int d, long long int s) {
  if (s == 1)
    return d;
  else if (s == 0)
    return 1;
  else {
    long long int u, v = d;
    for (u = 1; u < s; u++) {
      d = d * v;
    }
    return d;
  }
}
long long int count_divisors(long long int b) {
  long long int i, count = 0, n = 1;
  for (i = 2; i * i <= b; i++) {
    count = 0;
    if (b % i == 0) {
      while (b % i == 0) {
        b = b / i;
        count++;
      }
      n = n * (count + 1);
    }
  }
  if (b > 1) n = 2 * n;
  return n;
}
long long int bigmod(long long int a, long long int b, long long int mod) {
  if (b == 0) return 1;
  long long int x = bigmod(a, b / 2, mod);
  x = (x * x) % mod;
  if (b % 2) x = (x * a) % mod;
  return x;
}
long long int phi(long long int n) {
  double result = n;
  for (long long int p = 2; p * p <= n; ++p) {
    if (n % p == 0) {
      while (n % p == 0) n /= p;
      result *= (1.0 - (1.0 / (double)p));
    }
  }
  if (n > 1) result *= (1.0 - (1.0 / (double)n));
  return (long long int)result;
}
map<long long int, long long int> mp, mpp;
long long int a[2000012];
int main() {
  long long int n, i, z, k, ans;
  cin >> n;
  for (i = 1; i < 34; i++) {
    z = powe(2, i);
    k = (z + 1) / 2;
    z = (z - 1) * k;
    if (n % z == 0) {
      ans = z;
    } else if (z > n)
      break;
  }
  cout << ans;
}
