#include <iostream>
using namespace std;
int a[100],k;
int main()
{
	int x,y;
	scanf("%d %d",&x,&y);
	for(int i=x;i<=y;i++)
	{
		if((i%4==0&&i%100!=0)||i%400==0){
			a[k++]=i;
		}
	}
	cout<<k<<endl;
	for(int i=0;i<k;i++) cout<<a[i]<<" ";
}