def PointM(X,Y):
  n = len(X)
  xG = 0 ; yG = 0
  for i in range(n):
    xG = xG+X[i]
    yG = yG+Y[i]
  xG = xG/n
  yG = yG/n
  return xG,yG


X = [1,3,5,7]
Y = [2,4,6,8]
print(PointM(X,Y))