求助！超时！

#include<bits/stdc++.h>
using namespace std;
int month[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int palindrome(int aa){
    int ss=0;
    while(aa){
        ss=ss*10+aa%10;
        aa/=10;
    }
    return ss;
}
bool isRn(int year){
    return (year%4==0&&year%100!=0)||year%400==0;
}
int main(){
    int a,b,ans=0;
    cin>>a>>b;
    for(int i=a;i<=b;++i){
        int x=i/10000,y=i/100%100,z=i%100;
        if(isRn(x)) month[2]=29;
        else month[2]=28;
        if(palindrome(i)==i){
            if(((y<=12)&&(y>0))&&((z<=month[y])&&(z>0)))
            ans++;
        }
    }
    cout<<ans;
    return 0;
}