Type
 Vector=Array[1..3] of real;

Var
 A,B:Vector;
 i:Byte;

Function RadGr(X:Real):Real;
begin
 RadGr:=(X/Pi)*180;
end;

Function ArcCos(X:Real):Real;
begin
 if X=1 then ArcCos:=0 else
 if X=-1 then ArcCos:=Pi else
  ArcCos:=(Pi/2)-ArcTan(X/Sqrt(1-X*X));
end;

Function Norm(T:Vector):Real;
begin
 Norm:=Sqrt(Sqr(T[1])+Sqr(T[2])+Sqr(T[3]));
end;

Function Scal_Prod(T1,T2:Vector):Real;
var
 k:byte;
 S:Real;
begin
 S:=0;
 for k:=1 to 3 do S:=S+T1[k]*T2[k];
 Scal_Prod:=S;
end;

Function Angle(T1,T2:Vector):Real;
begin
 Angle:=RadGr(ArcCos(Scal_Prod(T1,T2)/(Norm(T1)*Norm(T2))));
end;

Begin
 Randomize;
 for i:=1 to 3 do
  begin
   A[i]:=(Random-0.5)*10;
   B[i]:=(Random-0.5)*10;
  end;
 Writeln('Vector A:');
 Writeln('(',A[1]:6:3,',',A[2]:7:3,',',A[3]:7:3,')');
 Writeln('Vector B:');
 Writeln('(',B[1]:6:3,',',B[2]:7:3,',',B[3]:7:3,')');
 Writeln('Angle: ',Angle(A,B):0:3,' deg.');
 Readln
End.