#include<bits/stdc++.h>
using namespace std;
int main()
{
	ios::sync_with_stdio(false);
	long long x,y,s=0,a[1001];
	cin>>x>>y;
	long long i;
	for(i=x;i<=y;i++)
	{
		if(i%4==0&&i%100!=0)
		{
			s+=1;
			a[i]=i;
		}
		else if(i%100==0&&i%400==0)
		{
			s+=1;
			a[i]=i;
		}
		else
		{
			continue;
		}
	}
	cout<<s<<"\n";
	for(i=x;i<=y;i++)
	{
		cout<<a[i]<<" ";
	}
}