def is_prime(N):
    i = 2
    while i * i < N:
        if N % i == 0:
            return False
        i += 1
    return True

L, H = map(int, input().split())

nums = [i for i in range(L,H+1)]

for n in nums:
    if is_prime(n):
        nums.remove(n)

i = 2
while i * i < H:
    j = 0
    while len(nums) > j:
        if len(nums) == 1:
            ans = nums[j]
            break
        if nums[j] % i == 0:
            nums.pop(j)
            continue
        j += 1
    i += 1

print(ans)