def step():
    def step_a(_p, _ms): return _p + 2, _ms + 2
    def step_b(_p, _ms): return _p - 1, _ms + 1
    
    pos, moved = (0, 0); yield pos, moved
    while True:
        pos, moved = step_a(pos, moved); yield pos, moved
        pos, moved = step_a(pos, moved); yield pos, moved
        pos, moved = step_b(pos, moved); yield pos, moved
        pos, moved = step_b(pos, moved); yield pos, moved
        pos, moved = step_a(pos, moved); yield pos, moved
        pos, moved = step_b(pos, moved); yield pos, moved
        pos, moved = step_b(pos, moved); yield pos, moved

x = int(input())
for (pos, moved) in step():
    if pos == x:
        print(moved)
        break