Question 187
Find a set $S$ of positive integers such that no two distinct subsets of $S$ have the same sum. Your score will be $\left\lfloor 20\left(2^{n} / r-2\right)\right\rfloor$, where $n$ is the number of elements in the set $S$, and $r$ is the largest element of $S$ (assuming, of course, that this number is nonnegative).