Yelena chants P, Q, R, S, T, U repeatedly (e.g. P, Q, R, S, T, U, P, Q, R, . . .). Zeno chants 1, 2, 3, 4 repeatedly (e.g. 1, 2, 3, 4, 1, 2, . . .). If Yelena and Zeno begin at the same time and chant at the same rate, which combination will not be said?