Determining vertical slices Given an image, output the [width in pixels of a full vertical section]1 (if one exists). If no vertical section exists, output 0.

Input may be provided as a local file or a nested array. If you choose to take input as a nested array, white pixels should be represented by a truthy value while non-white pixels should be represented by a falsey value.

1. the number of contiguous, all-white columns



You can assume that


no image will be larger than 1000 square pixels
there will be no more than one full vertical section per image




Examples

Inputs:






Outputs:

50
57
0
0


Here are the first two examples, highlighted (in yellow) to show their sections:
Jelly, 2 bytes

PS


Try it here!

If I encode an image like so:

0000111111111100000
0000000111111111000
0000000001111100000
0000000011111000000
0001111111111111100
0000001111110000000
0000000111111110000
0000111111111100000


Into a nested array like this:

[[0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0],[0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0],...]


Then P takes the element-wise product of all of the row vectors, and S sums all of the ones in the result, yielding the length of the vertical slice. (This works only because there’s guaranteed to be only one contiguous slice.) In our case, the answer is 3.