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,i): 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(",".join(map(str,t)) if t else "No") ## 如果t不为空，打印绝对素数列表，否则打印'No'