HONI '13

snaga.cpp

#include <bits/stdc++.h>

using namespace std;

#define double long long

double gcd(double a, double b)
{
	double tmp;
	while (b)
	{
		tmp = b;
		b = a % b;
		a = tmp;
	}
	return a;
}

double lcm(int n)
{
	double ret = 1;
	for (int i = 2; i <= n; ++i)
		ret *= i / gcd(ret, i);
	return ret;
}

double arr[4];

double calc(double n)
{
	double ret = 2 * n;
	ret += n / 2;
	for (int i = 0; i < 4; ++i)
	{
		double k = arr[i];
		ret += n / k + (n % k >= k / 2);
	}
	return ret;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	
	for (int i = 0; i < 4; ++i)
		arr[i] = lcm(4<<i);
	
	double a, b;
	
	cin>>a>>b;
	
	cout<<calc(b) - calc(a - 1)<<endl;
}