The probability of the first person winning is 1/n, and the probability of the second person winning according to the multiplication theorem should be the probability of the first person not winning multiplied by the conditional probability of the second person winning under this condition, that is, (n- 1)/n multiplied by1(n-1). Multiply the conditional probability of the third person smoking under the condition that neither of them smokes, that is, (n- 1)/n times (n-2)/(n- 1), and then multiply 1/(n-2), or1/n.