itertools.combinations().py

from itertools import combinations
st,*r = input().split()
for i in range(1,int(r[0])+1):
    for j in list(combinations(sorted(st),i)):
        print(*j,sep="")


# these are the more ways to find permutations

#>>> from itertools import combinations
#>>> 
#>>> print list(combinations('12345',2))
#[('1', '2'), ('1', '3'), ('1', '4'), ('1', '5'), ('2', '3'), ('2', '4'), ('2', '5'), ('3', '4'), ('3', '5'), ('4', '5')]
#>>> 
#>>> A = [1,1,3,3,3]
#>>> print list(combinations(A,4))
#[(1, 1, 3, 3), (1, 1, 3, 3), (1, 1, 3, 3), (1, 3, 3, 3), (1, 3, 3, 3)]