import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################


n = ni()
x = 1
while n > 0:
    if x % 7 == 0:
        n += 5
    else:
        n -= 1
    x += 1
print(x-1)