A gardener planted the mangoes trees in a mathematical ordered way (i.e. he planted tree in rows).

He created total of 19 rows of trees.

Note: There should be more than 2 trees to count as a row.

What is the minimum number of trees required by the gardener to have 19 rows of trees ?

A B C

E F G H

I J K L

M N O P

R S T

5 horizontal rows

4 vertical columns

4 diagonals with slope 1 (ROL, NKH, MJG, IFC)

4 diagonals with slope -1 (SNI, TOJE, PKFA, LGB)

2 knight's move diagonals with slope -2 (AJS, BKT)