def sum_gp(a,n,r):
 import math
 
 total = (a * (1 - math.pow(r, n ))) / (1- r)
 return total
def sum_gp(a, n, VAR_0):
    import math
   
    total = (a * (1 - math.pow(VAR_0, n))) / (1 - VAR_0)
    return total