my program is very easy:
Const
    InFile    = '1116.in';
    Limit    = 3000;
    LimitLen    = 30001;
    nodomain    = 127;

Type
    Tline    = array[-LimitLen..LimitLen] of shortint;

Var
    A , B ,
    C    : Tline;

procedure init;
var
    N , i ,
    x , y , F ,
    t    : integer;
begin
    for i := -LimitLen to LimitLen do
      begin
          A[i] := nodomain;
          B[i] := nodomain;
      end;
{    assign(INPUT , InFile); ReSet(INPUT);}
      read(N);
      for i := 1 to N do
        begin
            read(x , y , F);
            for t := x to y - 1 do
              A[t] := F;
        end;
      readln;
      read(N);
      for i := 1 to N do
        begin
            read(x , y , F);
            for t := x to y - 1 do
              B[t] := F;
        end;
      readln;
{    Close(INPUT);}
end;

procedure work;
var
    i    : integer;
begin
    for i := -LimitLen to LimitLen do
      if A[i] = nodomain then
        C[i] := A[i]
      else
        if B[i] = nodomain then
          C[i] := A[i]
        else
          C[i] := nodomain;
end;

procedure out;
var
    result     : array[1..Limit , 1..3] of integer;
    all , i    : integer;
begin
    i := -Limit;
    all := 0;
    while i <= Limit do
      if C[i] = nodomain then
        inc(i)
      else
        begin
            inc(all);
            result[all , 1] := i;
            inc(i);
            while C[i] = C[i - 1] do
              inc(i);
            result[all , 2] := i;
            result[all , 3] := C[i - 1];
        end;
    write(all);
    for i := 1 to all do
      write(' ' , result[i , 1] , ' ' , result[i ,
2] , ' ' , result[i , 3]);
    writeln;
end;

Begin
    init;
    work;
    out;
End.