#include<iostream>
using namespace std;
int main()
{
	int x = 0, y = 0, sum = 0, i = 0, j = 0;
	int arr[10000]{};
	cin >> x >> y;
	for (; x <= y; x++)
	{
		if (((x % 100 != 0) && (x % 4 == 0)) || (x % 400 == 0))
		{
			arr[i] = { x };
			sum++;
			i++;
		}
	}
	cout << sum << endl;
	j = i;
	for (i = 0; i <= j; i++)
	{
		cout << arr[i] << " ";
	}
	return 0;
}