(T+T+, p+p+)
(p+p+)
(g+g+, T+T+, p+p+)
(T+T+, p+p+, g+g+) and (T+T+, p+p+, g+g+, T+T+)
(p+p+, g+g+) and (p+p+, g+g+, T+T+)
(g+g+, T+T+, p+p+, g+g+) and (g+g+, T+T+, p+p+, g+g+, T+T+)
keeping in mind that given equal number of g+g+ particles, the lower position of p+p+ in the set increases mass, and assuming that the addition of a T+T+ particle does not change mass.
Here, we are one short of the seven discovered Hydrogen isotopes. Where's the last?
Note: Cyclic permutation, the particles are added in specific order. No swapping of position nor adding other types of particle please.