Try this in Python 3:
both = int(“10000000000000000000000000000000000000000000000000000000”)
k = 5
n = int((both - k)/2)
print(n + k)
print(n)
n = int((both - k)//2)
print(n + k)
print(n)
Then take a look here for an explanation.
Even if this were a bug, are you expecting SPOJ to fix Python?