n = int(input())
ans = 0

for a in range(0, 10):
	for b in range(0, 10):
		if a == b:
			continue
		ok = max(a, b)
		ng = 10 ** 9 + 1
		while ng - ok > 1:
			mid = (ok + ng) // 2
			if mid * mid - 1 < n * (mid * a + b):
				ok = mid
			else:
				ng = mid
		ans += ok - max(a, b)

print(ans)