SSC CHSL 6 Mar 2018 Shift 3 Paper

Series : UY, SV, QS, OP, ?
The pattern followed in each letter of the terms is :
1st letter : U (-2 letters) = S (-2 letters) = Q (-2 letters) = O (-2 letters) = M
2nd letter : Y (-3 letters) = V (-3 letters) = S (-3 letters) = P (-3 letters) = M
Thus, missing term = MM