#include <iostream>
using namespace std;
int main()
{
	int A,B,sum;
	cin >> A >> B;
	for (int i = A; i <= B; i++)
	{
		if (i % 4 == 0 && i % 100 != 0 || i % 400 == 0)
		{
			if (i % 3200 != 0) sum++;
		}	
	}
	cout << sum << endl;
	return 0;
}