#include<bits/stdc++.h>
using namespace std;

int main()
{
	int x,y,z = 0;
	int a[3001];
	cin>>x>>y;
	for(int i = x;i<=y;i++)
	{
		if(i%4==0&&i%400==0||i%100!=0)
		{
			z++;
			a[z] == i;
		}
	}
	cout<<z<<endl;
	for(int i = 1;i<=z;i++)
	{
		cout<<a[i]<<" ";
	}
}