  We demonstrate that the energy spectra of Ultra High Energy Cosmic Rays
(UHECR) as observed by AGASA, Fly's Eye, HiRes and Yakutsk detectors, have the
imprints of UHE proton interaction with the CMB radiation as the dip centered
at $E\sim 1\times 10^{19}$ eV, beginning of the GZK cutoff, and very good
agreement with calculated spectrum shape. This conclusion about proton
composition agrees with recent HiRes data on elongation rate that support the
proton composition at $E\geq 1\times 10^{18}$ eV. The visible bump in the
spectrum at $E \sim 4\times 10^{19}$ eV is not caused by pile-up protons, but
is an artifact of multiplying the spectrum by $E^3$. We argue that these data,
combined with small-angle clustering and correlation with AGN (BL Lacs), point
to the AGN model of UHECR origin at energies $E \leq 1\times 10^{20}$ eV. The
events at higher energies and the excess of the events at $E \geq 1\times
10^{20}$ eV, which is observed by AGASA (but absent in the HiRes data) must be
explained by another component of UHECR, e.g. by UHECR from superheavy dark
matter.
