MathDB

We have a

(n+2)\times n

rectangle and we’ve divided it into

n(n+2) \ \ 1\times1

squares.

n(n+2)

soldiers are standing on the intersection points (

n+2

rows and

n

columns). The commander shouts and each soldier stands on its own location or gaits one step to north, west, east or south so that he stands on an adjacent intersection point. After the shout, we see that the soldiers are standing on the intersection points of a

n\times(n+2)

rectangle (

n

rows and

n+2

columns) such that the first and last row are deleted and 2 columns are added to the right and left (To the left

1

and

1

to the right). Prove that

n

is even.

Problem Statement