usaco Prime Palindromes

/*
ID: yueqiq
LANG: C++
TASK: pprime
*/
#include <set>
#include <map>
#include <ctime>
#include <queue>
#include <cmath>
#include <stack>
#include <limits>
#include <vector>
#include <bitset>
#include <string>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <string.h>
#include <iostream>
#include <algorithm>
#define ls rt<<1
#define rs rt<<1|1
#define Si set<int>
#define LL long long
#define pb push_back
#define PS printf(" ")
#define Vi vector<int>
#define LN printf("\n")
#define SD(a) scanf("%d",&a)
#define PD(a) printf("%d",a)
#define SET(a,b) memset(a,b,sizeof(a))
#define FF(i,a) for(int i(0);i<(a);i++)
#define FD(i,a) for(int i(a);i>=(1);i--)
#define FOR(i,a,b) for(int i(a);i<=(b);i++)
#define FOD(i,a,b) for(int i(a);i>=(b);i--)
#define readf freopen("input.txt","r",stdin)
#define writef freopen("output.txt","w",stdout)
const double pi = acos(-1.0);
const int maxn = 1001;
const int BigP = 9999999;
const int INF = 99999999;
const int dx[]={0,1,0,-1};
const int dy[]={1,0,-1,0};
using namespace std;
bool prime[BigP+1000];
int A,B;
void IsPrime(){
prime[0]=prime[1]=0;prime[2]=1;
for(int i=3;i<BigP;i++)
prime[i]=i%2==0?0:1;
int t=(int)sqrt(BigP*1.0);
for(int i=3;i<=t;i++)
if(prime[i])
for(int j=i*i;j<BigP;j+=2*i)
prime[j]=0;
}
bool ishui(int k){
int ans=0,t,tmp;
tmp=k;
while(k){
t=k%10;
k/=10;
ans=ans*10+t;
}
//PD(ans);
if(ans==tmp) return true;
return false;
}
int main(){
IsPrime();
readf;
writef;
SD(A);SD(B);
FOR(i,A,B){
if(i<10000000){
if(prime[i] && ishui(i)){ PD(i);LN;}
}else break;
}
//ishui(12321);
return 0;
}