#include<bits/stdc++.h>
#define int long long
using namespace std;
signed main()
{
	int a , b , sum = 0;
	cin >> a >> b;
	for(int i = a;i <= b;i++)
	{
		if(i % 2 != 0 || i % 4 == 0) sum++;
	}
	cout << sum;
	return 0;
}