def prime_table(n):
    table = [0 for _ in xrange(n+1)]
    i = 2
    while i * i <= n:
        if table[i] == 0:
            j = i + i
            while j <= n:
                if table[j] == 0:
                    table[j] = i
                j += i
        i += 1
    return table

L, H = map(int, raw_input().split())
pt = prime_table(10**5+1)
mv, mi = 0, -1
for i in xrange(L, H+1):
    if pt[i] >= mv:
        mv = pt[i]
        mi = i
print mi