#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++)
    {
        cin >> arr[i];
    }
    sort(arr, arr + n);

    vector<int> freq;
    for (int i = n-2; i >= 0; i--)
    {
        int diff = abs({arr[i+1]-arr[i]});
        freq.push_back(diff);

        if(i == 0) freq.push_back(arr[i]);
    }
    
    sort(freq.begin(), freq.end(), greater<int>());
    for (int i = 0; i < freq.size(); i++)
    {
        if(freq.size() == 1) {
            cout<<freq[i]<<endl;
            break;
        }
        
        if(i < freq.size()-1 && freq[i] == freq[i+1]) {
            cout<<freq[i]<<endl;
            break;
        }
    }
    
    return 0;
}