... We understand its sorrow.
In reference to a song of Brassens.
No, I don't regret...

A lot of edge-logic. Some helps are available at the end of description.

Difficulty : ****

Tested, logical.
Hints:
- Edge-logic can help to place the 11 of C1.
- Edge-logic can help to place three cells of the 6 from R1 (to move the first step from the right, consider both the 6 and the 2).
- Edge-logic can help to "sufficiently" move down the 13 from C15, thanks to R7.
- The 3 from C16 induce a cross at least in each association of four successive cells in this column, what allows you to place a cell of the 4 from C14 thanks to the 13.
- Edge-logic can help to complete R25 (looking one time up to two rows above).
Good blackenage.