#include<iostream>
using namespace std;
int main(){
    int a,b,sum=0,q[sum];
    cin>>a>>b;
    for(int i=a;i<=b;i++){
        if(i%4==0&&i%100!=0||i%400==0){
            sum++;
            q[sum-1]=i;
        }
    }
    cout<<sum<<endl;
    for(int j=0;j<sum;j++){
        cout<<q[j]<<' ';
    }
    return 0;
}