My program is giving correct output but the run time gets exceeded, please help in optimizing the code :)

from itertools import product

n1, n2, n3, n4 = map(int,input().split())

l=[]

c=0

for i in range (n2):

l.append(i+1)

for i in product(l, repeat= n1):

if (sum(sorted(i, reverse= True) [:n3]) == n4):

    c+=1

print (c)