declare fun {Trojkat A B C}
    local fun {Wb X}
         if X>0.0 then X else ~X end
          end
    in
        if {Wb (B-C)}<A andthen A<(B+C) then 'jupi' else 'nie' end
    end

    local P = (A+B+C)/ 2.0 in {Float.sqrt (P * (P - A) * (P - B) * (P - C))}

    end
end

{Show {Trojkat 1.0 2.0 3.0 }}