汽水瓶（python代码）

def printf(x):
    total = 0
    c = x//3
    total = total+c
    d = x%3
    x = d+c
    if x >3:
        while x>3:
            c = x//3
            total = total+c
            d = x%3
            x = d+c
        if x == 2:
            total += 1
        elif x==3:
            total+=1
    elif x==2:
        total+=1
    elif x==3:
        total+=1
    print(total)
b = []
while True:
    a = int(input())
    if a == 0:
        break
    b.append(a)
for i in range(len(b)):
    printf(b[i])