k=int(input())
n=int(input())
isprime=[True]*(n+1)
isprime[0]=False
isprime[1]=False
for i in range(2, n+1):
    if isprime[i]:
        for j in range(2*i, n+1, i):
            isprime[j]=False
prime=[i for i, b in enumerate(isprime) if b and i>=k]
def digitsum(x):
    s=0
    while x>0:
        s+=x%10
        x//=10
    return s%9
d=[digitsum(x) for x in prime]
ans=(0, 0)
l=len(prime)
for i, p in enumerate(prime):
    b=0
    for j in range(i, min(i+9, l)):
        if b&(1<<d[j]):
            ans=max(ans, (j-i, p))
            break
        b^=(1<<d[j])
    else:
        ans=max(ans, (l-i, p))
print(ans[1])