import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int[] a = new int[n]; a new int[n] n for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			a[i] = sc.nextInt();
		} {
			a[i] = sc.nextInt();
		} a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc int result = Integer.MIN_VALUE; result Integer.MIN_VALUE Integer Integer.MIN_VALUE for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			} for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			} int j = 0; int j = 0; j 0 j < n j n j++ j++ j {
				result = Math.max(a[i] - a[j], result);
			} {
				result = Math.max(a[i] - a[j], result);
			} result = Math.max(a[i] - a[j], result) result Math.max(a[i] - a[j], result) Math.max Math a[i] - a[j] a[i] a i a[j] a j result System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		int result = Integer.MIN_VALUE;
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++) {
				result = Math.max(a[i] - a[j], result);
			}
		System.out.println(result);
	}
}