{$A+,B-,D+,E+,F-,G-,I+,L+,N-,O-,P-,Q-,R-,S+,T-,V+,X+}
{$M 16384,0,655360}

program TALLAGE;

 type Coord=record
   X, Y: real;
 end;

 type Rebr=record
   B, E: integer;
   Z: real;
   f: boolean;
 end;

 const D=3;

 var
   N, i, j, t, k, count: integer;
   sum: real;
   V: array[1..D] of Coord;
   L, Kark: array[1..D*(D-1)] of Rebr;
   P: array[1..D] of integer;

 procedure PLength (s1, s2: integer; var Res: real);
 begin
   Res:=Sqrt (Sqr (Abs (V[s1].X - V[s2].X)) + Sqr (Abs (V[s1].Y - V[s2].Y)));
 end;

 procedure Zap (i1, i2: integer);
  var
    j: integer;
 begin
  for j:=1 to N do
    if P[j]=i2 then P[j]:=i1;
 end;

 procedure Kraskala;
  var
    i, j: integer;
    pr: Rebr;
 begin
  count:=0;
  for i:=1 to N-1 do
    for j:=i+1 to N do
      if L[i].Z>L[j].Z then
       begin
         pr:=L[i];
         L[i]:=L[j];
         L[j]:=pr;
       end;
  for i:=1 to N do
   begin
     if P[L[i].B] <> P[L[i].E] then
      begin
        inc (count);
        Kark[count]:=L[i];
        if P[L[i].B] > P[L[i].E] then Zap (L[i].E, L[i].B)
         else Zap (L[i].B, L[i].E);
      end;
   end;
 end;

begin
 Assign (Input, 'TALLAGE.DAT');
 Reset (Input);
 Read (N);
 i:=1;
 while i<=N do
  begin
    Read (V[i].X, V[i].Y);
    inc (i);
  end;
 k:=-2;
 for i:=1 to N do
  begin
    inc(k);
    for j:=1 to N do
      if i<>j then
       begin
         t:=k+j;
         if L[t].f then Continue;
         PLength (i, j, L[t].Z);
         L[t].B:=i;
         L[t].E:=j;
         L[t].f:=true;
       end;
  end;
 for i:=1 to N do
   P[i]:=i;
 Close (Input);
 Kraskala;
 Assign (Output, 'TALLAGE.RES');
 Rewrite (Output);
 sum:=0;
 for i:=1 to count do
   sum:=sum+Kark[i].Z;
 Writeln (sum:3:3);
 for i:=1 to count do
   Writeln (Kark[i].B, ' ', Kark[i].E);
 Close (Output);
end.