digraph CFG {
  node [fontname="Helvetica"];
  n107 [label="START", shape=ellipse, style=filled, color=gray];
  n107 -> n119;
  n119 [label="1", shape=box];
  n119 -> n120;
  n120 [label="CALL a", shape=box, style=filled, color=orange];
  n120 -> n109;
  n120 -> n122;
  n109 [label="START a(x)", shape=ellipse, style=filled, color=green];
  n109 -> n116;
  n116 [label="x", shape=box];
  n116 -> n110;
  n110 [label="END a(x)", shape=ellipse, style=filled, color=green];
  n110 -> n122;
  n122 [label="RET a", shape=box, style=filled, color=orange];
  n122 -> n124;
  n124 [label="2", shape=box];
  n124 -> n125;
  n125 [label="CALL b", shape=box, style=filled, color=orange];
  n125 -> n111;
  n125 -> n127;
  n111 [label="START b(y)", shape=ellipse, style=filled, color=green];
  n111 -> n117;
  n117 [label="y", shape=box];
  n117 -> n112;
  n112 [label="END b(y)", shape=ellipse, style=filled, color=green];
  n112 -> n127;
  n127 [label="RET b", shape=box, style=filled, color=orange];
  n127 -> n128;
  n128 [label="3", shape=box];
  n128 -> n129;
  n129 [label="CALL c", shape=box, style=filled, color=orange];
  n129 -> n113;
  n129 -> n131;
  n113 [label="START c(z)", shape=ellipse, style=filled, color=green];
  n113 -> n118;
  n118 [label="z", shape=box];
  n118 -> n114;
  n114 [label="END c(z)", shape=ellipse, style=filled, color=green];
  n114 -> n131;
  n131 [label="RET c", shape=box, style=filled, color=orange];
  n131 -> n108;
  n108 [label="END", shape=ellipse, style=filled, color=gray];
}