A double Mertens type evaluation

We prove the formula ∑ p q ≤ x 1 p q = ( ln ( ln x ) + B ) 2 − ln 2 2 + 2 ∫ 0 + 0 1 2 ln ( 1 − x ) x d x + O ( ln ( ln x ) ln x ) , where B is the Mertens constant.