begin 
comment library 1;
    real 
        x,
        y;
    procedure dum;
        ;

    real procedure a;
        a := x + (if b then 1 else 0);

    boolean 
        b;
    s2 :;
    b := ((true ));
    g :;
    begin 
        integer 
            i;
        x := - 3;
        if ! b then 
            go to s2;
        i := 1;
        y := a - i * x^2;
        dum
    end;
    outreal(1, y / 2)
end