import numpy as np
   
def readInput(filename, sensor1ID = 1, sensor2ID = 2):
   XInput = np.genfromtxt(filename,delimiter=',')
   
   X1 = XInput[np.where(XInput[:,0] == sensor1ID)[0]]
   X2 = XInput[np.where(XInput[:,0] == sensor2ID)[0]]
   N = np.min((X1.shape[0], X2.shape[0]))
   
   X1 = X1[:N-1,:]
   X2 = X2[:N-1,:]
   
   return((X1, X2))