problem {#loops}
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The convective zones are determined by the Ledoux criterion. It seems to be more justified than the Schwarzschild criterion because of a direct sensitivity of the chemical gradient to evolution. Lebreton et al. (2009) argued that the use of the Ledoux criterion leads to a narrower ICZ and hence to the smaller number of unstable modes. In case of our models, MESA produces the wide ICZ with both criterions and this effect is not significant. For the envelope, we adopted the parameter of the mixing length theory (MLT) of $\alpha_\mathrm{mlt}=1.8$ which is the higher value than usually used for massive stars. During the main sequence (MS) and hydrogen-shell burning phases, the value of $\alpha_\mathrm{mlt}$ has a negligible effect on structure of massive stars but on the red giant branch (RGB) a higher efficiency of convection is needed and hence we opted for the higher value of $\alpha_\mathrm{mlt}$. We took into account convective overshooting from the hydrogen and helium core and inward overshooting from non-burning convective zones, using the exponential formula (Herwig 2000): $$\label{overshooting}
  D_\mathrm{OV} = D_\mathrm{conv}\exp(-\frac{2z}{fH_P}),$$ where $D_\mathrm{conv}$ is the diffusion coefficient derived from MLT at a user-defined location near the boundary of a convective zone, $H_P$ 