  The fusion and evaporation residue cross sections for the
$^{50}$Ti+$^{249}$Cf and $^{54}$Cr+$^{248}$Cm reactions calculated by the
combined dinuclear system and advanced statistical models are compared. These
reactions are considered to be used to synthesize the heaviest superheavy
element. The $^{50}$Ti+$^{249}$Cf reaction is more mass asymmetric than
$^{54}$Cr+$^{248}$Cm and the fusion excitation function for the former reaction
is higher than the one for the latter reaction. The evaporation residue
excitation functions for the mass asymmetric reaction is higher in comparison
with the one of the $^{54}$Cr+$^{248}$Cm reaction. The use of the mass values
of superheavy nuclei calculated in the framework of the macroscopic-microscopic
model by the Warsaw group leads to smaller evaporation residue cross section
for both the reactions in comparison with the case of using the masses
calculated by Peter M\"oller {\it et al}. The $^{50}$Ti+$^{249}$Cf reaction is
more favorable in comparison with the $^{54}$Cr+$^{248}$Cm reaction: the
maximum values of the excitation function of the 3n-channel of the evaporation
residue formation for the $^{50}$Ti+$^{249}$Cf and $^{54}$Cr+$^{248}$Cm
reactions are about 0.1 and 0.07 pb, respectively, but the yield of the
4n-channel for the former reaction is lower (0.004 pb) in comparison with the
one (0.01 pb) for the latter reaction.
