#include <bits/stdc++.h>
#define MAX_R  999

std::vector<std::string> prepare()
{
	std::vector<std::string> v;
	for (int_least16_t i = 0; i <= 295; ++i)
		v.push_back(std::string("C++"));
	for (int_least16_t i = 296; i <= 416; ++i)
		v.push_back(std::string("Rust"));
	for (int_least16_t i = 417; i <= MAX_R; ++i)
		v.push_back(std::string("Python"));

	return v;
}

int_least16_t solve(const int_least16_t L, const int_least16_t R)
{
	int_least16_t ans = 0;
	for (int_least16_t i = L; L <= i && i + 1 <= R; ++i)
	{
		std::vector<std::string> v = prepare();
		ans += (v[i] != v[i + 1]);
	}

	return ans;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	int_least16_t L, R;
	std::cin >> L >> R;

	std::cout << solve(L, R) << '\n';
	return 0;
}