def average_Even(n) :
     
    if (n% 2!= 0) : 
        return ("Invalid Input") 
        return -1  
    sm = 0
    count = 0
    while (n>= 2) : 
        count = count+1
        sm = sm+n 
        n = n-2
    return sm // count 
def average_Even(to):
    if to % 2 != 0:
        return "Invalid Input"
        return -1
    sm = 0
   
    count = 0
    while to >= 2:
        count = count + 1
        sm = sm + to
        to = to - 2
    return sm // count