THUMBNAIL NORMALIZE

Difficulty: Easy Tags: Computer Vision, Data Processing

Story

Netflix normalizes every uploaded artwork candidate before it reaches the thumbnail-ranking CNN. Get the normalization wrong and the model silently sees out-of-distribution inputs with no error thrown anywhere.

The Math

x' = (x - mu) / sigma

where mu and sigma are the mean and population standard deviation of the pixel values in the given image.

Input Format

H W
p_1,1 ... p_1,W
...
p_H,1 ... p_H,W

Output Format

First line: mu and sigma. Then the H x W normalized matrix, row by row, all to 6 decimals.

Constraints

• 1 <= H, W <= 512
• Time limit: 1.0 second.

Example

Input

2 2
100 150
200 250

Output

175.000000 55.901699
-1.341641 -0.447214
0.447214 1.341641