import sys
import lib
from collections import defaultdict


data = open(0).read().strip()


def more_efficient_part_1(data):
    def corners():
        layer = 0
        corner = 1
        edge_len = 3
        yield (corner, layer, edge_len)
        while True:
            corner += (edge_len - 1) * 4
            layer += 1
            yield (corner, layer, edge_len)
            edge_len += 2

    square = int(data)
    corner, layer, edge_len = 0, 0, 0
    for corner, layer, edge_len in corners():
        if square < corner:
            break

    coord = (layer, layer)
    while corner != square:
        for dir in [(0, -1), (-1, 0), (0, 1), (1, 0)]:
            for _ in range(edge_len - 1):
                corner -= 1
                coord = lib.add2(coord, dir)
                if corner == square:
                    break
            if corner == square:
                break
    return sum(map(abs, coord))



def walk_spiral():
    yield (0, 0), 1
    yield (0, 1), 2

    value = 2
    coord = (0, 1)
    step_len = 1

    up = (-1, 0)
    left = (0, -1)
    down = (1, 0)
    right = (0, 1)


    while True:
        for _ in range(step_len):
            coord = lib.add2(coord, up)
            value += 1
            yield coord, value

        step_len += 1

        for _ in range(step_len):
            coord = lib.add2(coord, left)
            value += 1
            yield coord, value

        for _ in range(step_len):
            coord = lib.add2(coord, down)
            value += 1
            yield coord, value

        step_len += 1
        for _ in range(step_len):
            coord = lib.add2(coord, right)
            value += 1
            yield coord, value

values = defaultdict(int)
values[(0, 0)] = 1
part_1 = False

for coord, value in walk_spiral():
    if part_1 and value == int(data):
        print(sum(map(abs, coord)))
        break

    nval = 0
    for d in lib.nbs8:
        nb = lib.add2(coord, d)
        nval += values[nb]

    if nval > 0:
        values[coord] = nval

    if nval > int(data):
        print(nval)
        break