10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
const long double eps = 1e-12;
const long long MOD = 1e9 + 7;
int dx[4] = {1, 0, 0, -1};
int dy[4] = {0, 1, -1, 0};
void fail() {
  cout << "NO";
  exit(0);
}
void win() {
  cout << "YES";
  exit(0);
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
int a[300300];
int n;
long double f(long double x) {
  long double ans = -1e9;
  for (int i = 0; i < n; i++) ans = max(ans, fabs(a[i] - x));
  return ans;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  int mn = 1e9, mx = -1e9;
  for (int i = 0; i < n; i++) {
    mn = min(mn, a[i]);
    mx = max(mx, a[i]);
  }
  cout.precision(10);
  cout << fixed << double(mx - mn) / 2;
  return 0;
}
