My python code:

```
if x<0:
neg = True
else:
neg=False
num = abs(x)
lst = []
while(num>0):
r = num%10
num = num//10
lst.append(r)
mul = 1
sum = 0
for i in range(len(lst)-1,-1,-1):
sum+=lst[i]*mul
mul = mul*10
if neg == False:
return sum
else:
return (0-sum)
```

it doesnot pass a test case where the program says the output for 1534236469 should be 0. I dont get it.