include<stdio.h>

int main() {

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

}