import sys
from itertools import permutations
input = sys.stdin.readline

n = int(input())

ans = 0
for a, b in permutations([*range(10)], 2):
    def func(p, a, b):
        return (p ** 2 < n * (p * a + b) + 1)
    min_p = max(a, b) + 1
    if not(func(min_p, a, b)):
        continue
    ok = min_p
    ng = 10 ** 9 + 1
    while(abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if func(mid, a, b):
            ok = mid
        else:
            ng = mid
    ans += ok - min_p + 1

print(ans)