>>139505903*3 is too small
4*4 is the smallest integer side square
does there exist a 3.?? sided square that can fit more than 9 unit squares?
no, since to fit another more than 9 squares you necessarily need at least one row/column of 4 squares
so a square with side a doesn't fit more squares a square with side floor(a)
so 4*4 is the minimum
picrel is an example of square with side about 3.5