I want to create a program wich gives me all possible combination to make a certain number.

So, lets say i want all possible ways to make 15 with 3 digits with the numbers 1 till 9 (9 included), this is simple:

```
# python2
result = []
for a in range(1,10):
for b in range(1,10):
for c in range(1,10):
x = [a,b,c]
x.sort()
if a + b + c == 15:
if len(set(x)) == 3:
if x not in result:
result.append(x)
print result
```

with 4 or 5 digits, its also easy, you just add one or two more loops. The part where i get stuck is if i let the user choice how many digits he wants (3, 4 or 5 digits), because then, i can't hard code the loop.

Can somebody help me in the right direction?