#v = primary vector
#w = secondary vector
def dprod(v, w):
    i = 0
    s = 0
    if len(v) == len(w):
        while i <= len(v)-1:
            s = s + (v[i]*w[i])
            i=i+1
    else:
        print("Sorry, cannot be done!")
    return s
v = [3, 5, 2]
w = [6, 9, 3]
print(dprod(v, w))