If there are no positive numbers in the given set, then there is at most one number equal to zero, and all other numbers are negative, which means that there are $n-1$ negative numbers. Therefore, as the required set of 2 numbers, we can take any two numbers.

Otherwise, if there is at least one positive number in this set, we will isolate this number. Among the other $n-1$ numbers that remained, we take any 2 numbers. If their sum is negative, then the required set is found and the problem is solved. If the sum is non-negative, then we add the previously isolated positive number to this sum. If the new sum is positive, then we have found the required set of 3 numbers. Otherwise, the sum of all three numbers is non-positive, which means that the required set of 2 numbers with a negative sum is also found.