  We present an evidence of strong radial flow in high-multiplicity pp
collisions. We analyze the CMS data on the inclusive spectra of the charged
pions, kaons and protons in the LHC $\sqrt{s}=7$ TeV collisions. For
$<N_{\mathrm{tracks}} >\gtrsim 75$ we demonstrate the consistency of the
hydrodynamic description with the (idealized) Gubser's flow. Using a one
parameter fit of the model to experimental data, we obtain the initial fireball
size to be of the order of 1 fm. At smaller multiplicities, the fit cannot be
performed which shows a limitation of the hydrodynamic approach and provides us
with falsifiability of our theory.
