The nuclei involved in the nuclear reaction A1+A2→A_{1}+A_{2} \rightarrowA1+A2→ →A3+A4\rightarrow A_{3}+A_{4}→A3+A4 have the binding energies E1,E2,E3,E_{1}, E_{2}, E_{3},E1,E2,E3, and E4.E_{4} .E4. Find the energy of this reaction.