include

using namespace std;

int main() {

int x, y;
cin >> x >> y;
int r = 0;
for (int i = x; i <= y; i++) {
	if ((i % 400 == 0) || (i % 100 != 0) && (i % 4 == 0))
		r = r + 1;
}
cout << r;
return 0;

}