Euclid's algorithm

import sys
def __block_1__():
        __block_2__()
def __block_2__():
        global b,a
        b,a=None,None
        __block_3__()
 def __block_3__():
        global b,a
        a=int(raw_input())
        __block_4__()
 def __block_4__():
        global b,a
        b=int(raw_input())
        __block_5__()
 def __block_5__():
        global b,a
        if a==b:
                __block_6__()
        else:
                __block_7__()
 def __block_6__():
        global b,a
        __block_8__()
 def __block_8__():
        global b,a
        sys.exit(0)
 def __block_7__():
        global b,a
        if a<b:
                __block_9__()
        else:
                __block_10__()
 def __block_9__():
        global b,a
        b=b-a
        __block_5__
 def __block_10__():
        global b,a
        a=a-b
        __block_5__
__block_1__()