小白求助，TLE，感觉时间复杂度太大了

def f(x):
    if x==1:
        return None
    if x==2:
        return 2
    else:
        a=0
        for i in range(2,x):
           if x%i==0:
               a=0
               break
           else:
               a=1
        if a==1:
            return x
a,b=map(int,input().split())
for i in range(a,b+1):
    if str(i)==str(i)[::-1] and f(i)!=None:
        print(i)