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