Problem 44882. Opposite point of the earth, what is the antipodal of a point ?

Given two strings(lat and long) that represent the geographic coordinates of a point in the earth, you have to find out what is the opposite or most farthest point of the earth from that point(antipodal). The strings will be 'r.dd C', where r is the real part, dd(the mantissa in decimal, not in minutes and dd can be present or not with the form dd,d or '<nothing>', equal the point(.)) and C the cardinal point (S,N,E or W). You have to return two strings (lat and long) with the same format that the input.

Extra question: What is the opposite point of north pole? And why is not possible to calculate it by this method ?

Suppose the earth is spherical, not flat (Lol)