#include<bits/stdc++.h>
#define int long long
using namespace std;
int a[3001],ans;
signed main()
{
	int x,y;cin>>x>>y;
	for(int i=x;i<=y;i++)
	{
		if(i%4==0||(i%100!=0&&i%400==0)) ans++;
	}
	cout<<ans<<'\n';
	for(int i=x;i<=y;i++)
	{
		if(i%4==0||(i%100!=0&&i%400==0))  cout<<i<<" ";
	}
}