#include<bits/stdc++.h>
using namespace std;
long long sum;
int a,b;
int main(){
	cin>>a>>b;
	for(int i=a;i<=b;++i){
		if(a%400==0)
			sum+=a;
		else if(a%100==0)
			;
		else if(a%4==0)
			sum+=a;
	}
	cout<<sum;
	return 0;
}