never {
accept_init:
s1_init:
    if
    :: (q) && !(r) -> goto accept_s3
    :: (p) && (q) && !(r) -> goto s2
    :: !(q) -> goto s1_init
    :: (r) -> goto s1_init
    fi;
s2:
    if
    :: (r) -> goto s1_init
    :: (p) && !(r) -> goto s2
    fi;
accept_s3:
    if
    :: !(r) -> goto accept_s3
    fi;
}