import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int[] arr = new int[n]; for (int i = 0; i < n; i++) { arr[i] = sc.nextInt(); } Arrays.sort(arr); for (int i = 1; i < n; i++) { if (arr[i] == arr[i - 1] + 1) { System.out.println(2); return; } } System.out.println(1); } }