let write a logic for "All my friends are perfect"
$\vee x(q(x)\rightarrow p(x))$
take negation of above "none of my friends are perfect"
$\sim(\vee x(q(x)\rightarrow p(x)))$
$\sim\vee x (\sim q(x)\vee p(x))))$
$Ǝx(q(x)\wedge \sim p(x))$
Correct me if I am wrong.