  We show that the difference cross sections in unpolarized SIDIS e+N\to e+h+X
and pp hadron production p+p\to h+X determine, uniquely and in any order in
QCD, the two FFs: D_u^{h-\bar h} and D_d^{h-\bar h}, h=\pi^\pm, K^\pm. If both
K^\pm and K_s^0 are measured, then e+e-\to K+X, e+N\to e+K+X and p+p\to K+X
yield independent measurements of (D_u-D_d)^{K^+ +K^-}. In a combined fit to
K^\pm and K^0_s production data from e+e- collisions, (D_u-D_d)^{K^++K^-} is
obtained and compared to conventional parametrizations.
