Imagine having an unbiased six-faced die, and you have the freedom to roll it as many times as you wish. Calculate the number of distinct ways you can achieve a sum of 20 by adding the outcomes of the dice rolls.
Example: The sum of 3 can be achieved in the following 4 ways:
1. 1st throw: 1, 2; 2nd throw: 1, 3; 3rd throw: 1
2. 1st throw: 1, 2; 2nd throw: 2
3. 1st throw: 2, 2; 2nd throw: 1
4. 1st throw: 3
Note: Put the answer as an integer without any padded zeroes or decimal points. For example, if the answer is 1, then please put 1 as the answer and not 1.0 or 01 or 001. If you think that there can be an unlimited number of ways, then put -1 as the answer.
