include <bits/stdc++.h>

using namespace std;

int main() {

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

}