#include <iostream>
#include <vector>
#include <list>
using namespace std;

class Node { 
  public:
    vector <class Node *> edges; 
    int tmp; 
}; 

class Graph { 
  public: 
     vector <Node *> nodes; 
     int Shortest_Path(Node *a, Node *b); 
}; 

int Graph::Shortest_Path(Node *a, Node *b)
{
  int i;
  list <Node *> bfsq;
  list <Node *>::iterator bit;
  Node *n;

  for (i = 0; i < nodes.size(); i++) nodes[i]->tmp = -1;
  a->tmp = 0;
  bfsq.push_back(a);

  while (!bfsq.empty()) {
    bit = bfsq.begin();
    n = *bit;
    bfsq.erase(bit);
    if (n == b) return n->tmp;
    for (i = 0; i < n->edges.size(); i++) {
      if (n->edges[i]->tmp == -1) {
        n->edges[i]->tmp = n->tmp+1;
        bfsq.push_back(n->edges[i]);
      }
    }
  }
  return -1;
}

main()
{
  Graph g;
  Node *n;
  int i, j;

  for (i = 0; i < 10; i++) {
    n = new Node;
    g.nodes.push_back(n);
  }

  for (i = 0; i < 9; i++) {
    g.nodes[i]->edges.push_back(g.nodes[i+1]);
  }

  cout << g.Shortest_Path(g.nodes[0], g.nodes[9]) << endl;
  cout << g.Shortest_Path(g.nodes[9], g.nodes[0]) << endl;

  for (i = 0; i < 10; i++) {
    for (j = 0; j < i; j++) {
      g.nodes[i]->edges.push_back(g.nodes[j]);
    }
  }

  cout << g.Shortest_Path(g.nodes[0], g.nodes[9]) << endl;
  cout << g.Shortest_Path(g.nodes[9], g.nodes[0]) << endl;
}