import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        int n = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        int left = 0;
        int right = n;
        while (right - left > 1) {
            int m = (left + right) / 2;
            PriorityQueue<Integer> queue = new PriorityQueue<>();
            for (int i = 0; i < m; i++) {
                queue.add(-t);
            }
            boolean flag = true;
            for (int i = n - 1; i >= 0; i--) {
                int x = queue.poll();
                if (x + arr[i] > 0) {
                    flag = false;
                    break;
                }
                queue.add(x + arr[i]);
            }
            if (flag) {
                right = m;
            } else {
                left = m;
            }
        }
        System.out.print(right);
    }
}