struct Node {
  int i;
  Node next;
  bool hasNext
}

int minus(int x, int y) { return x - y; }

int plus(int x, int y) { return x + y; }

int fold_str_int(Node n, (int, int) -> int f, int base) {
  if(n.hasNext) {
    var newBase = f(base, n.i);
    return fold_str_int(n.next, f, newBase);
  } else {
    return f(base, n.i);
  }
}
  

int program(int argc, string[] argv) {
  var n9 = new Node {i=9; next=Node null; hasNext=false};
  var n8 = new Node {i=8; next=n9; hasNext=true};
  var n7 = new Node {i=7; next=n8; hasNext=true};
  var n6 = new Node {i=6; next=n7; hasNext=true};
  var n5 = new Node {i=5; next=n6; hasNext=true};
  var n4 = new Node {i=4; next=n5; hasNext=true};
  var n3 = new Node {i=3; next=n4; hasNext=true};
  var n2 = new Node {i=2; next=n3; hasNext=true};
  var n1 = new Node {i=1; next=n2; hasNext=true};
  return fold_str_int(n1, plus, 0) - fold_str_int(n1, minus, 2);
}