static void Main()
{
var(n, m, s, t) = Read4();
var p = Read();
var map = GraphConsole.ReadUnweightedMap(n + 1, m, false);
int x = p[s - 1], y = 0;
var u = new bool[n + 1];
var q = PriorityQueue <int> .CreateWithKey(v => p[v - 1], true);
u[s] = true;
q.Push(s);
while (q.Any)
{
var(v, pv) = q.Pop();
if (x > pv)
{
x = pv;
y++;
}
foreach (var nv in map[v])
{
if (u[nv])
{
continue;
}
u[nv] = true;
q.Push(nv);
}
}
Console.WriteLine(y);
}
static object Solve()
{
Console.ReadLine();
var(n, m) = Read2();
var map = GraphConsole.ReadUnweightedMap(n + 1, m, true);
var r = map.Bfs(1);
var dp = Array.ConvertAll(new bool[n + 1], _ => - 1L);
void Dfs(int v)
{
if (dp[v] >= 0)
{
return;
}
dp[v] = r[v];
foreach (var nv in map[v])
{
if (r[nv] <= r[v])
{
dp[v] = Math.Min(dp[v], r[nv]);
}
else
{
Dfs(nv);
dp[v] = Math.Min(dp[v], dp[nv]);
}
}
}
Dfs(1);
return(string.Join(" ", dp[1..]));
static object Solve()
{
Console.ReadLine();
var(n, m) = Read2();
var map = GraphConsole.ReadUnweightedMap(n + 1, m, true);
var r = map.Bfs(1);
var dp = r.RawCosts.ToArray();
var q = Enumerable.Range(1, n).Select(v => (v, d: r[v])).OrderBy(t => - t.d);
foreach (var(v, d) in q)
{
foreach (var nv in map[v])
{
if (r[nv] <= r[v])
{
dp[v] = Math.Min(dp[v], r[nv]);
}
else
{
dp[v] = Math.Min(dp[v], dp[nv]);
}
}
}
return(string.Join(" ", dp[1..]));
static void Main()
{
var(n, m) = Read2();
var map = GraphConsole.ReadUnweightedMap(n + 1, m, false);
var r = map.Bfs(1);
Console.WriteLine("Yes");
Console.WriteLine(string.Join("\n", r.RawInVertexes[2..]));
static object Solve()
{
var(n, m) = Read2();
var map = GraphConsole.ReadUnweightedMap(n + 1, m, true);
var r = 0;
for (int v = 1; v <= n; v++)
{
var result = map.Bfs(v);
r += result.RawCosts.Count(x => x != long.MaxValue);
}
return(r);
}