component C1 {
  system {
    C2  c2;
    C3 c3;
  }
}

component C2 {
  system {
    C5 c5;
  }
}

component C3 {
  system {
    C4 c4;
    C2 c2;
  }
}

component C4 {
  system {
    C1 c1;
  }
}

component C5 {
  system {
  }
}