include

using namespace std;

int main() {

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

}