from itertools import cycle
import sys


def main():
    input = lambda: sys.stdin.readline()[:-1]
    X = int(input())

    ab = (2, 2, -1, -1, 2, -1, -1)
    ans, x = 0, 0
    for n in cycle(ab):
        x += n
        ans += abs(n)
        if x == X:
            print(ans)
            break


if not __debug__:
    f = open(sys.argv[1], "r")
    sys.stdin = f


main()