In Python 3.x, use this.
a = [int(x) for x in input().split()]
Example
>>> a = [int(x) for x in input().split()]
3 4 5
>>> a
[3, 4, 5]
>>>
In Python 3.x, use this.
a = [int(x) for x in input().split()]
>>> a = [int(x) for x in input().split()]
3 4 5
>>> a
[3, 4, 5]
>>>