'''
MADDI.UMASHANKAR
N190348 CSE-E1
RGUKT,NUZVID
'''
import numpy as us
n=int(input("Enter no.of variables: "))
print("The no.of subsets are:",2**n)
print("Enter the elements:")
Set=[input() for i in range(n)]
print("The subsets are:")
def Subset(L):
x=[]
for i in range(n):
if L[i]==1:
x.append(Set[i])
print(x)
def Binary_convert(n):
i=-1
while n!=0:
x=n%2;L[i]=x;i-=1;n//=2
Subset(L)
L=us.zeros(n,int)
for i in range(2**n):
Binary_convert(i)