MathDB

There is a city with

n

metro stations, each located at a vertex of a regular n-polygon. Metro Line 1 is a line which only connects two non-neighboring stations

A

and

B

. Metro Line 2 is a cyclic line which passes through all the stations in a shape of regular n-polygon. For each line metro can run in any direction, and

A

and

B

are the stations which one can transfer into other line. The line between two neighboring stations is called 'metro interval'. For each station there is one stationmaster, and there are at least one female stationmaster and one male stationmaster. If

n

is odd, prove that for any integer

k

(0<k<n)

there is a path that starts from a station with a male stationmaster and ends at a station with a female stationmaster, passing through

k

metro intervals.

Problem Statement