var
 x1, y1, z1, x2, y2, z2, vastus:integer;
 v2, nurk: real;
 begin
  writeln('Sisesta vektori v koordinaadid!');
  readln(x1);
  readln(y1);
  readln(z1);
  writeln('Sisesta vektori u koordinaadid!');
  readln(x2);
  readln(y2);
  readln(z2);
  writeln('Arvutame skalaarkorrutise.');
  vastus:=abs(x1*x2+y1*y2+z1*z2);
  writeln('Vastus on ',vastus,'. Arvutame ka vektorite vahelise nurga.');
  v2:=vastus/(sqrt(sqr(z1)+sqr(x1)+sqr(y1))*sqrt(sqr(z2)+sqr(x2)+sqr(y2)));
  if v2=0 then writeln('Tekib nulliga jagamine') else
    nurk:=arctan(sqrt(1-sqr(v2))/v2);
  writeln('Vektorite vaheline nurk on ',nurk:5:3);
  readln;
 end.