The transverse-momentum-integrated yield ratio of $\phi$/$\pi$ (left)  and ${\rm f_1}$/$\pi$ (right) measured in inelastic pp collisions at $\s$ = 13 TeV. The statistical and systematic uncertainties on the data points are shown as bars and boxes, respectively. The black solid and dotted lines represent the calculations from the $\gamma_{\rm S}$CSM with different strangeness content of $\phi$ and ${\rm f_1}$ mesons.