62nd Ukrainian National Mathematical Olympiad

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.