import sys
def test():
for line in sys.stdin:
n= line.strip()
num=int(n)
if num!=0:
number=0
num=num+1
while num>2:
a=num//3
b=num%3
num=a+b
number+=a
print(number)
else:
return 0
test()
def test():
for line in sys.stdin:
n= line.strip()
num=int(n)
if num!=0:
number=0
num=num+1
while num>2:
a=num//3
b=num%3
num=a+b
number+=a
print(number)
else:
return 0
test()