include <stdio.h>

int main() {

int a,b,c,sum=0;
scanf("%d%d",&a,&b);
c=a;
while(c<=b)
{
if(c%4==0&&c%100!=0||c%400==0)
{
    sum++;
}  
    c++;
}
printf("%d",sum);
return 0;

}