A radionuclide A1 goes through the transformation chain A1+ A2 A3 (stable) with respective decay constants 1

Question:

A radionuclide A1 goes through the transformation chain A1+ A2 → A3 (stable) with respective decay constants λ1 = and λ2. Assuming that at the initial moment the preparation contained only the radionuclide Ax equal in quantity to N10 nuclei; find the equation describing accumulation of the stable isotope A3.