Average of Nonnegative Values

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Given n real numbers, ignore negative values and average all nonnegative ones, including zero. Output EMPTY if none exist. Inputs have at most two decimal places. Round the nonnegative mean to two decimals, with exact half-cent ties rounded up.

Input

First line: n (0<=n<=10000). Exactly n decimal numbers follow, each in [-10^6,10^6] with at most two decimal places.

Output

Print EMPTY if no nonnegative values exist. Otherwise print the mean with exactly two digits after the decimal point, using half-up rounding.

Subtasks

• Subtask 1 (20%): $n\le5, |a_i|\le10$.
• Subtask 2 (30%): $n\le100,|a_i|\le1000$.
• Subtask 3 (50%): $n\le10000,|a_i|\le10^6$.

Examples

Example 1

Input:

5
-1.00 0.00 2.00 4.00 -3.00

Output:

2.00

Explanation:

Keep 0, 2 and 4, with mean 2.00.

Example 2

Input:

3
-0.10 -5.00 -3.01

Output:

EMPTY

Explanation:

All three values are negative, so no average can be computed.

Example 3

Input:

2
0.00 0.01

Output:

0.01

Explanation:

The exact mean 0.005 rounds up to 0.01.