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

void bucketSort(int* arr, int n, int k) {
    queue<int> q0, q1;
    for (int i = 0; i < n; i++) {
        if (arr[i] & (1<<k)) {
            q1.push(arr[i]);
        } else {
            q0.push(arr[i]);
        }
    }
    int i = 0;
    while (!q0.empty()) {
        arr[i] = q0.front();
        q0.pop();
        i++;
    }
    while(!q1.empty()) {
        arr[i] = q1.front();
        q1.pop();
        i++;
    }
}

void radixSort(int* arr, int n) {
    for (int i = 0; i < 32; i++) {
        bucketSort(arr, n, i);
    }
}

int maxDiff(int* arr, int n) {
    if (n < 2) {
        return 0;
    }
    radixSort(arr, n);
    int m = arr[1] - arr[0];
    for (int i = 1; i < n-1; i++) {
        if (arr[i+1] - arr[i] > m) {
            m = arr[i+1] - arr[i];
        }
    }
    return m;
}

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