#include <bits/stdc++.h>

[[nodiscard]] static inline constexpr uint_fast32_t solve(const uint_fast32_t N) noexcept
{
	uint_fast32_t ans = 0;
	for (uint_fast32_t i = 1; i <= N; ++i)
		if (i % 10 == 8 || i / 10 % 10 == 8 || i / 100 % 10 == 8)
			++ans;

	return ans;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);

	uint_fast32_t N;
	std::cin >> N;

	std::cout << solve(N) << '\n';
	return 0;
}