Shares of sea and valence quarks in the proton spin puzzle

The first moments of the polarized valence PDFs truncated to the wide Bjorken $x$ region $0.004<x<0.7$ are directly (without any fitting procedure) extracted in NLO QCD from the combined semi-inclusive DIS data of COMPASS and HERMES. Applying the proposed original procedure to these results we estimate the contributions of light sea quarks to the proton spin, which occur just zero within the errors.