#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int hjysb,hjydsb;
int dhw(int a,int b)
{
	int i;
	int ans=0;
	int sg[10001];
	memset(sg,0,sizeof(sg));
	for(i=a;i<=b;i++)
	{
		if((i%4==0 && i%100!=0) || i%400==0)
		{
			sg[i]=i;
			ans++;
		}
	}
	printf("%d\n",ans);
	for(i=1582;i<=3000;i++)
	{
		if(sg[i]!=0)
		{
			printf("%d ",sg[i]);
		} 			
	}
}
int main()
{
	scanf("%d %d",&hjysb,&hjydsb);
	printf("%d",dhw(hjysb,hjydsb));
	return 0;
}