#include<bits/stdc++.h>
using namespace std;
int main(){
	freopen("leapyear.in","r",stdin);
    freopen("leapyear.out","w",stdout);
	int x,y,sum=0;
	cin>>x>>y;
	for(int i=x;i<=y;i++){
		if(i%4==0&&i%100!=0||i%400==0){
			sum++;
		}
	}
	cout<<sum;
	return 0;
}