package no385;

import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static int INF = 1 << 29;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int m = sc.nextInt();
		int n = sc.nextInt();
		int[] c = new int[n];
		for(int i=0;i<n;i++) {
			c[i] = sc.nextInt();
		}
		int[] dp = new int[m+1];
		Arrays.fill(dp, -INF);
		dp[0] = 0;
		for(int i=0;i<n;i++) {
			for(int j=c[i];j<=m;j++) {
				dp[j] = Math.max(dp[j], dp[j-c[i]] + 1);
			}
		}
//		System.out.println(Arrays.toString(dp));
		long ans = 0;
		boolean[] isPrime = isPrimeArray(m);
		for(int i=0;i<m;i++) {
			if (isPrime[i] && dp[m-i] >= 0) {
				ans += dp[m-i];
			}
		}
		int max = 0;
		for(int i=0;i<=m;i++) {
			max = Math.max(max, dp[i]);
		}
		ans += max;
		System.out.println(ans);
	}
	
	public static boolean[] isPrimeArray(int max) {
		boolean[] isPrime = new boolean[max+1];
		Arrays.fill(isPrime, true);
		isPrime[0] = isPrime[1] = false;
		for(int i=2;i*i<=max;i++) {
			if (isPrime[i]) {
				int j = i * 2;
				while(j<=max) {
					isPrime[j] = false;
					j += i;
				}
			}
		}
		return isPrime;
	}

}