K = int(input())

N = int(input())

p = [0] * 2 + [1] * N

for i in range(2, int(N ** 0.5) + 2):
    
    if p[i]:
        
        for j in range(2 * i, N + 1, i):
            
            p[j] = 0
            
P = [i for i in range(K, N + 1) if p[i]]
p = len(P)
for i in range(min(9, p), 0, -1):
    
    for j in range(p - i, -1, -1):
        
        x = [0] * 9
        
        for k in range(j, j + i):
            
            x[P[k] % 9] += 1
        if max(x) == 1:
            print(P[j])
            exit()