const fi = 'CHIADAGIAC.INP';
      fo = 'CHIADAGIAC.OUT';
      MAXN = 100;
      oo = MAXINT;

var  f:text;
     n: integer;
     a, b: array[1..MAXN] of real;
     H: array[1..MAXN, 1..MAXN] of integer;
     L: array[1..MAXN, 1..MAXN] of real;
     //L[i, j] tong do dai cac duong cheo
     //khi xet tu dinh i den dinh j
     d: array[1..MAXN, 1..MAXN] of real;
     //d la do dai duong cheo giua dinh i va j

procedure Nhap;
var i:integer;
begin
    assign(f, fi); reset(f);
    readln(f, n);
    for i:= 1 to n do readln(f, a[i], b[i]);
    close(f);
    //a[n+1] := a[1];
    //b[n+1] := b[1];
end;

function KhoangCach(i, j: integer):real;
begin
    exit(sqrt(sqr(a[i]-a[j])+sqr(b[i]-b[j])));
end;

procedure TinhKhoangCachCacDuongCheo;
var i, j: integer;
begin
        for i:= 1 to n do
        begin
                d[i, i]:= 0;
                d[i, i mod n + 1]:= 0;
                d[i mod n + 1, i]:= 0;
        end;

        for i:= 1 to n do
                for j:= 1 to i-1 do
                        if (i <> j) and (abs(i-j) <> 1) then
                        begin
                                d[i, j]:= KhoangCach(i, j);
                                d[j, i]:= d[i, j];
                        end;
end;

function min(a, b:real):real;
begin
    if a<b then exit(a) else exit(b);
end;

procedure QHD;
var i, j, m, k: integer;
    tong :real;
begin
    fillchar(L, sizeof(L), 0);
    // m = j - i

    for m:=3 to n-1 do
        for i:=1 to n-m do
        begin
            j := i+m;
            L[i,j] := +oo;
            for k:= i to j-1 do
            begin
                 tong:= L[i, k] + L[k,j] + d[i, k] + d[k, j];

                 if L[i, j] > tong then
                 begin
                        L[i, j]:= tong;
                        H[i, j]:= k;
                 end;
            end;
        end;
end;

procedure TruyVet(i, j:integer);
var k:integer;
begin
        if j - i >= 3 then
        begin
              k:= H[i, j];
              writeln(f, 'Noi dinh ', i, ' voi dinh ', k);
              writeln(f, 'Noi dinh ', k, ' voi dinh ', j);
              TruyVet(i, k);
              TruyVet(k, j);
        end;
end;


BEGIN
        Nhap;
        QHD;
        assign(f, fo); rewrite(f);
        writeln(f, L[1, n]:0:2);
        TruyVet(1, n);
        close(f);
END.