public static void Solve()
{
var(first, last) = Scanner.Scan <string, string>();
if (first == last)
{
Printer.Print(0);
Printer.Print(first);
Printer.Print(last);
return;
}
var N = Scanner.Scan <int>();
var W = new List <string>();
W.Add(first);
for (var i = 0; i < N; i++)
{
var w = Scanner.Scan <string>();
if (w != first && w != last)
{
W.Add(w);
}
}
W.Add(last);
W = W.Distinct().ToList();
var G = new List <int> [W.Count].Select(x => new List <int>()).ToArray();
var length = first.Length;
for (var i = 0; i < W.Count - 1; i++)
{
for (var j = i + 1; j < W.Count; j++)
{
if (i == j)
{
G[i][j] = 0; continue;
}
var count = 0;
for (var k = 0; k < length && count < 2; k++)
{
if (W[i][k] != W[j][k])
{
count++;
}
}
if (count != 1)
{
continue;
}
G[i].Add(j);
G[j].Add(i);
}
}
var queue = new Queue <int>();
queue.Enqueue(0);
var depths = Enumerable.Repeat(-1, W.Count).ToArray();
depths[0] = 0;
var parent = new int[W.Count];
while (queue.Any())
{
var current = queue.Dequeue();
foreach (var next in G[current])
{
if (depths[next] != -1)
{
continue;
}
depths[next] = depths[current] + 1;
parent[next] = current;
queue.Enqueue(next);
}
}
var answer = depths[^ 1];