This code passes for test0 and fails fro all of others I didn't understand the reason.

import math 

un, b = map(int, input().split() )

def function(x,b): 
        return math.floor(2**(b-x**2))*10**(-9) 

for _ in range(10**5):
        un1 = un
        un = function( un1, b)

print(un + un1)