include <stdio.h>

int main() {

int x, y, s;
s = 0;
scanf("%d %d", &x, &y);
while (x <= y) {
	if (x % 4 == 0 && x % 100 != 0 || x % 400 == 0) {
		s = s + 1;
	}
	x = x + 1;
}
printf("%d", s);
return 0;

}