Hi,

I always recieve a non zero exit code?

Why is that happening?

Could someone look at my code?

```
def fact(n):#factorial function
if(n==0):
return 1
return(n*fact(n-1))
def coeff(n,k):#binomial coefficient
return(fact(n)/fact(k)/fact(n-k))
#define {0,1,2...2^n-1} as range(2**n)
def compute(n,r):
#what in given set matches criteria
cr=[]
for k in range(2**n):
if((coeff(((2**n)-1),k))%(2**n))==r:
cr.append(k)
#now compute minimum and return value
if(len(cr)>0):
return min(cr)
else:
return -1
def main():
#no of test cases:-
t=input()
for i in range(t):
a=raw_input()
a=a.split(' ')
print compute(int(a[0]),int(a[1]))
return 0
main()
```