import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		try {
			Scanner scan = new Scanner(System.in);
			int N = scan.nextInt();
			int[] x = new int[N];
			int ans = Integer.MAX_VALUE;

			x[0] = scan.nextInt();
			for (int i = 1; i < N; ++i) {
				x[i] = scan.nextInt();
				for (int j = i - 1; j > 0; --j) {
					if (x[i] != x[j]) {
						if (ans > Math.abs(x[i] - x[j])) {
							ans = Math.abs(x[i] - x[j]);
						}
					}

				}
			}
			if(ans == Integer.MAX_VALUE){
				ans = 0;
			}
			System.out.println(ans);

			scan.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}