include <bits/stdc++.h>

using namespace std;

int main() {

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

return 0;

}