Can't understand where is my mistake :(

Var
   t, s, x, y, n : extended;
   i : longint;
begin
     readln(x, y, n);
     s := x*n;
     y := y + 0.05;
     for i := 1 to 10000000 do
         begin
              t := (s+i)/(n+i);
              if t < y then begin writeln(i); halt; end;
             end;
     writeln('Impossible');
end.