def reverse_prime(x,y): results=[] for i in range(x,y+1): a=str(i)[::-1] b=int(a) flag=True for j in range(2,int(i**0.5)+1): if i%j==0 or b%j==0: flag=False break else: results.append(i) return results x,y=map(int,input().split()) t=reverse_prime(x,y) print(t)