import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

from collections import deque



sys.setrecursionlimit(10**7)

inf = 10**20

mod = 10**9 + 7



DR = [1, -1, 0, 0]

DC = [0, 0, 1, -1]



def LI(): return [int(x) for x in sys.stdin.readline().split()]

def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]

def LF(): return [float(x) for x in sys.stdin.readline().split()]

def LS(): return sys.stdin.readline().split()

def I(): return int(sys.stdin.readline())

def F(): return float(sys.stdin.readline())

def S(): return eval(input())





def solve(x):

    rot = x // (6 + 5)

    res = x % (6 + 5)

    ans = 2 * rot

    # rot:evenなら、つぎに当たるのは6

    if res > 0 and rot % 2 == 0:

        if res <= 6:

            ans += 1

        else:

            ans += 2

    elif res > 0 and rot % 2 == 1:

        if res <= 5:

            ans += 1

        else:

            ans += 2

    else:

        pass

    return ans



def main():

    x = I()

    ans = solve(x)

    print(ans)

    # print()

    # for i in range(1, 30):

    #     print(i, solve(i))

main()



import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

from collections import deque



sys.setrecursionlimit(10**7)

inf = 10**20

mod = 10**9 + 7



DR = [1, -1, 0, 0]

DC = [0, 0, 1, -1]



def LI(): return [int(x) for x in sys.stdin.readline().split()]

def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]

def LF(): return [float(x) for x in sys.stdin.readline().split()]

def LS(): return sys.stdin.readline().split()

def I(): return int(sys.stdin.readline())

def F(): return float(sys.stdin.readline())

def S(): return eval(input())





def solve(x):

    rot = x // (6 + 5)

    res = x % (6 + 5)

    ans = 2 * rot

    # rot:evenなら、つぎに当たるのは6

    if 0 < res <= 6:

        ans += 1

    if 6 < res:

        ans += 2

    return ans



def main():

    x = I()

    ans = solve(x)

    print(ans)

main()



import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools
from collections import deque

sys.setrecursionlimit(10**7)
inf = 10**20
mod = 10**9 + 7
DR = [1, -1, 0, 0]
DC = [0, 0, 1, -1]


def LI():
    return [int(x) for x in sys.stdin.readline().split()]


def LI_():
    return [int(x) - 1 for x in sys.stdin.readline().split()]


def LF():
    return [float(x) for x in sys.stdin.readline().split()]


def LS():
    return sys.stdin.readline().split()


def I():
    return int(sys.stdin.readline())


def F():
    return float(sys.stdin.readline())


def S():
    return eval(input())


def solve(x):
    rot = x // (6 + 5)
    res = x % (6 + 5)
    ans = 2 * rot
    # rot:evenなら、つぎに当たるのは6
    if res > 0 and rot % 2 == 0:
        if res <= 6:
            ans += 1
        else:
            ans += 2
    elif res > 0 and rot % 2 == 1:
        if res <= 5:
            ans += 1
        else:
            ans += 2
    else:
        pass
    return ans


def main():
    x = I()
    ans = solve(x)
    print(ans)
    # print()
    # for i in range(1, 30):
    #     print(i, solve(i))


main()

import math, string, itertools, fractions, heapq, collections, re, array, bisect, sys, random, time, copy, functools
from collections import deque

sys.setrecursionlimit(10**7)
inf = 10**20
mod = 10**9 + 7
DR = [1, -1, 0, 0]
DC = [0, 0, 1, -1]


def LI():
    return [int(x) for x in sys.stdin.readline().split()]


def LI_():
    return [int(x) - 1 for x in sys.stdin.readline().split()]


def LF():
    return [float(x) for x in sys.stdin.readline().split()]


def LS():
    return sys.stdin.readline().split()


def I():
    return int(sys.stdin.readline())


def F():
    return float(sys.stdin.readline())


def S():
    return eval(input())


def solve(x):
    rot = x // (6 + 5)
    res = x % (6 + 5)
    ans = 2 * rot
    # rot:evenなら、つぎに当たるのは6
    if 0 < res <= 6:
        ans += 1
    if 6 < res:
        ans += 2
    return ans


def main():
    x = I()
    ans = solve(x)
    print(ans)


main()

-    if res > 0 and rot % 2 == 0: -        if res <= 6: -            ans += 1 -        else: -            ans += 2 -    elif res > 0 and rot % 2 == 1: -        if res <= 5: -            ans += 1 -        else: -            ans += 2 -    else: -        pass +    if 0 < res <= 6: +        ans += 1 +    if 6 < res: +        ans += 2 -    # print() -    # for i in range(1, 30): -    #     print(i, solve(i))