Fibonacci Sequence - Python Version

The theory:
This piece of code is the implementation of the Fibonacci series as shown in the previous post, rewritten in Python.

a=0
b=1
len=int (raw_input("Enter the length of the sequence "))
print "The sequence::"
print a,b
while len>2:
    c=a+b
    print c
    a=b
    b=c
    len=len-1

The output:
Enter the length of the sequence 7
The sequence::
0 1
1
2
3
5
8

When the length of the sequence is 50, what happens?
Enter the length of the sequence 50
The sequence::
0 1
1
2
3
5
8
13
21
34
55
89
144
233
377
610
987
1597
2584
4181
6765
10946
17711
28657
46368
75025
121393
196418
317811
514229
832040
1346269
2178309
3524578
5702887
9227465
14930352
24157817
39088169
63245986
102334155
165580141
267914296
433494437
701408733
1134903170
1836311903
2971215073
4807526976
7778742049

Notes:
No negative values were displayed here. Python is dynamically typed, in contrast to c which is statically typed. By default all data read from the user is string data. It is because of this I converted the variable len as I did - to int(). Else, an error would occur when trying to perform len=len-1. One more thing, python also does not allow increment or decrement (++ or --).