C++ :

#include <iostream>
#include <cmath>
using namespace std;

typedef long long Long;


int main()
{
	Long N, L, R;
	Long ret;
	while (cin >> N >> L >> R)
	{
		//L--;
		Long rr = (Long)sqrt(R);
		Long ll = (Long)sqrt(L-1);

		ret = R - L + 1 - rr + ll;

		cout << ret << endl;
	}

	return 0;
}