package net.ipipip0129.yukicoder.no135;

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        int cnt = Integer.parseInt(scan.nextLine());
        List<Integer> pos_list = new ArrayList<>();

        String[] lines = scan.nextLine().split(" ");

        for (int i = 0; i < cnt; i++) {
            pos_list.add(Integer.parseInt(lines[i]));
        }

        scan.close();

        pos_list = new ArrayList<>(new HashSet<>(pos_list));
        Collections.sort(pos_list);

        int min_num = -1;

        if (pos_list.size() != 1) {
            for (int i = 0; i < pos_list.size() - 1; i++) {
                if (min_num == -1){
                    min_num = pos_list.get(i + 1) - pos_list.get(i);
                }else if(pos_list.get(i + 1) - pos_list.get(i) < min_num) {
                    min_num = pos_list.get(i + 1) - pos_list.get(i);
                }
            }
            System.out.println(min_num);
        } else {
            System.out.println(0);
        }
    }
}