import java.util.*; import java.io.*; /** * Created by rajat goyal on 3/19/2017. */ public class PickingNumbers { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); int[] a = new int[n]; for(int a_i=0; a_i < n; a_i++){ a[a_i] = in.nextInt(); } pickNumbers(a, n); } public static void pickNumbers(int[] a, int n) { Arrays.sort(a); int max = 0; for (int i = 0; i < n; i++) { int j = i + 1, count = 1; while(j < n && a[j] <= a[i] + 1){ count++; j++; } if(count > max) max = count; } System.out.println(max); } }