Need tips for speeding up python code

[iineo]

from numpy import array, bitwise_or
from itertools import combinations, chain 

n,k=map(int,input().split())
arr=list(map(int,input().split()))
tup=map(list,chain.from_iterable(map(lambda x:combinations(arr,x),range(1,k+1)))) 
ans=map(lambda x:bitwise_or.reduce(array(x,dtype='int')),tup)
print(len(set(ans)))

n is the number of elements in set
the code makes subsets of size <= k and performs bitwise or on each subset and prints the number of unique elements formed