大神走过路过不要错过~最后一个点TLE！！~

#include<iostream>
#include<cmath>
using namespace std;
bool ok_2(int a)
{
    int m;
    int sum = 0;
    m = a;
    while(m)
    {
        sum = sum*10 + m%10;
        m /= 10; // m = m/10
    }
    if(sum == a)
        return 1;
    else
        return 0;
}
bool ok(int n)
{
    int m,i,k;
    m = n;
    k=(int)sqrt(m);
    for(i=2;i<=k;i++)
    if(m%i==0)
        break;
    if(i>k)
        return 1;
    else
        return 0;
}
int main()
{
    int l,r,s = 0;
    cin>>l>>r;
    if(l % 2 == 0)
        l--;
    for(int i = l;i <= r;i+=2)
    {
        if(ok_2(i))
            if(ok(i))
                cout<<i<<endl;
    }
    return 0;
}