I think what you are asked for is a discounted present cash value. since there is no interest rate given in this formula, the NV would be:
500.000/(1+i) + 500.000/(1+i)^2 + 500.000(1+i)^3
where i is your monthly interest rate. Therefore it is somewhat a monthly annuity. However, the problem description is very brief. Usually, a discount instrument is seen like a zero-bond with disagio. This is because they only have to be paid back when the discount period is over. It is basically like a capital market loan for start up. Venture capital most of the time.