#include <iostream>
#include <vector>
#include <map>
#include <string.h>
#include <math.h>
#include <set>
#include <stack>
#include <queue>
#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define cy cout << "YES\n"
#define cn cout << "NO\n"
#define nl "\n"
#define fi first
#define se second
#define MOD 1000000007
#define all(v) v.begin(), v.end()
#define rall(v) v.end(), v.begin()

#define sz(s) s.size()
#define f0r(j, n) for (ll i = j; i < n; i++)
template <typename T = int>
istream &operator>>(istream &in, vector<T> &v)
{
    for (auto &x : v)
        in >> x;
    return in;
}

template <typename T = int>
ostream &operator<<(ostream &out, const vector<T> &v)
{
    for (const T &x : v)
        out << x << " ";
    return out;
}

void sherry()
{
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}
/*
int gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return (b, a % b);
}
*/

void solve()
{
    int n;
    cin >> n;
    vector<int> v(n);
    cin >> v;
    set<int> st;
    sort(all(v));
    for (int i = 0; i < n - 1; i++)
    {
        st.insert(v[i + 1] - v[i]);
        if (i + 2 < n)
            st.insert(v[i + 2] - v[i]);
    }
    int i = 0;
    for (auto &x : st)
    {
        i++;
        if (i == 3)
        {
            cout << x << nl;
            return;
        }
    }
}
int main()
{
    sherry();
    int t = 1;
    // cin >> t;
    while (t--)
        solve();
    return 0;
}
// 5 1 0 3 4 2
// 2 5 5 6 7
// 3 1 0