var n, k, i, max, maxa, maxb, j: longint; a, b: array [-1..200000] of longint;
begin
  readln(n, k);
  a[-1] := -maxint-1;
  a[0] := -maxint-1;
  b[-1] := 1;
  b[0] := 1;
  for i := 1 to n do begin
    readln(a[i*2 - 1], a[i*2]);
    b[i*2 - 1] := 0;
    b[i*2] := 0;
  end;
  for i := 1 to k do begin
    max := -maxint-1;
    for j := 1 to n*2 do begin
      if (max < a[j] + a[j-2]) and (b[j] = 0) and (b[j-2] = 0) then begin
        max := a[j] + a[j-2];
        maxa := j;
        maxb := j-2;
      end;
      if (max < a[j] + a[j+2]) and (b[j] = 0) and (b[j+2] = 0) then begin
        max := a[j] + a[j+2];
        maxa := j;
        maxb := j + 2;
      end;
      if j div 2 = 1 then
        if (max < a[j] + a[j+1]) and (b[j] = 0) and (b[j+1] = 0) then begin
          max := a[j] + a[j+1];
          maxa := j;
          maxb := j + 1;
        end
      else
        if (max < a[j] + a[j-1]) and (b[j] = 0) and (b[j-1] = 0) then begin
          max := a[j] + a[j-1];
          maxa := j;
          maxb := j - 1;
        end;
    end;
    a[maxa] := -maxint-1;
    a[maxb] := -maxint-1;
    b[maxa] := i;
    b[maxb] := i;
  end;
  for i := 1 to n do writeln(b[i*2 - 1], ' ', b[i*2]);
end.