1 #include"bits/stdc++.h"
 2 #define ll long long
 3 #define ci(x) scanf("%d",&x)
 4 #define cd(x) scanf("%lf",&x)
 5 #define cl(x) scanf("%lld",&x)
 6 #define pi(x) printf("%d\n",x)
 7 #define pd(x) printf("%f\n",x)
 8 #define pl(x) printf("%lld\n",x)
 9 using namespace std;
10 const int N   = 1e6 + 5;
11 const int mod = 1e9 + 7;
12 ll a[N],b[N];
13 
14 ll mod_mul(ll a, ll b, ll mod) {
15     ll ret = 0;
16     while(b) {
17         if(b & 1)  ret = (ret + a) % mod;
18         a = (a + a) % mod;
19         b >>= 1;
20     }
21     return ret;
22 }
23 
24 ll mod_exp(ll a, ll b, ll mod) {
25     ll ret = 1;
26     while(b) {
27         if(b & 1) ret = mod_mul(ret, a, mod);
28         a = mod_mul(a, a, mod);
29         b >>= 1;
30     }
31     return ret;
32 }
33 
34 bool check(ll a, ll n) {
35     ll x = n - 1, y;
36     int t = 0;
37     while((x & 1) == 0) {
38         x >>= 1;
39         t++;
40     }
41     x = mod_exp(a, x, n);
42 
43     for(int i = 1; i <= t; i++) {
44         y = mod_exp(x, 2, n);
45         if(y == 1 && x != 1 && x != n - 1) return true;
46         x = y;
47     }
48     if(y != 1) return true;
49     return false;
50 }
51 
52 bool mill(ll n, int times = 10) {
53     if(n == 2) return true;
54     if(n == 1 || !(n & 1)) return false;
55 
56     for(int i = 1; i <= times; i++) {
57         ll a = rand() % (n - 1) + 1;
58         if(check(a, n)) return false;
59     }
60     return true;
61 }
62 int p=1,q=0;
63 int n;
64 int l,r;
65 void init()//预处理出所有的回文质数
66 {
67     string f,e;
68     a[0]=11;
69     for(ll i=5;i<=10000;i++){
70         e=to_string(i);
71         f=e;
72         reverse(f.begin(),f.end());
73         e=e+f;
74         ll x=(ll)atoi(e.data());
75         if(mill(x)==1) b[q++]=x;
76 
77         e=to_string(i);
78         f=e.substr(0,e.size()-1);
79         reverse(f.begin(),f.end());
80         e=e+f;
81         ll y=(ll)atoi(e.data());
82         if(mill(y)==1) a[p++]=y;
83     }
84     int k=0;
85     for(int i=p;i<p+q;i++) a[i]=b[k++];
86     sort(a,a+p+q);
87     n=p+q;
88 }
89 int main ()
90 {
91     init();
92     ios::sync_with_stdio(0);
93     cin>>l>>r;
94     for(int i=0;i<n;i++) if(l<=a[i]&&a[i]<=r) pl(a[i]);
95     return 0;
96 }