quase_primos

n, k = map(int, raw_input().split())

prims = map(int, raw_input().split())

mult = []
for i in range(len(prims)):
    for j in range(i, len(prims)):
        if i != j:
            number = prims[i]*prims[j]
            if number <= n: mult.append(number)

ans = n
for i in prims:
    last = n-(n%i)
    ans -= last/i

for i in mult:
    last = n-(n%i)
    ans += last/i

print ans