\version "2.19.80"

melodiaUno = \relative c' {
  \key c \major
  \time 4/4
  
  \mark \markup {\override #'(thickness . 4) \box \fontsize #2 "A"}
  r8 d e c \tuplet 3/2 { g'4 d e }
  
  d8( c~  c2.)
  r4 d8 ees c8. ees16 d8 c
  \bar "||"
  \key ees \major
}

\score {
  <<
    \new StaffGroup
    <<
      \context Staff {
        \new Voice {
          \melodiaUno
        }
      }
    >>
  >>
  \layout {
    indent = 0
    ragged-right = ##f
  }
}

melodiaDos = \relative c'' {
  \key ees \major
  \time 4/4
  
  \mark \markup {\override #'(thickness . 4) \box \fontsize #2 "B"}
  ees,8 d~  d2.
  r8 c d ees \tuplet 3/2 { g4 f ees }
  d4-. r2.
  \bar "||"
}

\score {
  <<
    \new StaffGroup
    <<
      \context Staff {
        \new Voice {
          \melodiaDos
        }
      }
    >>
  >>
  \layout {
    indent = 0
    ragged-right = ##f
    \override Score.TimeSignature.stencil = ##f
  }
}