#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
M, N, *C = map(int, read().split())

# %%
U = 10 ** 4 + 10
is_prime = [0] * U
is_prime[2] = 1
for i in range(3, U, 2):
    is_prime[i] = 1
for p in range(3, U, 2):
    if p * p > U:
        break
    for i in range(p * p, U, p + p):
        is_prime[i] = 0
primes = [i for i, x in enumerate(is_prime) if x]


# %%
INF = 10 ** 9
dp = [-INF] * (M + 1)
dp[M] = 0
for x in C:
    for n in range(M, x - 1, -1):
        y = dp[n] + 1
        if dp[n - x] < y:
            dp[n - x] = y


# %%
x = sum(max(0, dp[p]) for p in primes if p <= M)
x += max(dp)
print(x)