There are n cities and m roads in Berland. Each road connects a pair of cities. The roads in Berland are one-way.

What is the minimum number of new roads that need to be built to make all the cities reachable from the capital?

New roads will also be one-way.

Input

The first line of input consists of three integers n, m and s (1 ≤ n ≤ 5000, 0 ≤ m ≤ 5000, 1 ≤ s ≤ n) — the number of cities, the number of roads and the index of the capital. Cities are indexed from 1 to n.

The following m lines contain roads: road i is given as a pair of cities u_i, v_i (1 ≤ u_i, v_i ≤ n, u_i ≠ v_i). For each pair of cities (u, v), there can be at most one road from u to v. Roads in opposite directions between a pair of cities are allowed (i.e. from u to v and from v to u).

Output

Print one integer — the minimum number of extra roads needed to make all the cities reachable from city s. If all the cities are already reachable from s, print 0.

Examples

Input

9 9 1
1 2
1 3
2 3
1 5
5 6
6 1
1 8
9 8
7 1


Output

3


Input

5 4 5
1 2
2 3
3 4
4 1


Output

1

Note

The first example is illustrated by the following:

<image>

For example, you can add roads (6, 4), (7, 9), (1, 7) to make all the cities reachable from s = 1.

The second example is illustrated by the following:

<image>

In this example, you can add any one of the roads (5, 1), (5, 2), (5, 3), (5, 4) to make all the cities reachable from s = 5.
//package c490;

import java.util.*;
import java.awt.Color;
import java.awt.font.GraphicAttribute;
import java.io.*;

public class Eproblem 
{
	static boolean[] good;
	static boolean[] visit;
	static MyList1[] graph;
	//static MyList1[] revGraph;
	static int ans=0;
	static int count=0;
	
	public static void main (String[] wxargs)
	{
		FastReader reader = new FastReader();
		PrintWriter writer = new PrintWriter(System.out);
		
		int n = reader.nextInt();
		int m = reader.nextInt();
		int s = reader.nextInt()-1;
		
		graph = new MyList1[n];
		//revGraph = new MyList1[n];
		for (int i=0; i<n; i++)
		{
			graph[i] = new MyList1();
			//revGraph[i] = new MyList1();
		}
		
		good = new boolean[n];
		Arrays.fill(good, false);
		visit = new boolean[n];
		Arrays.fill(visit, false);
		
		for (int i=0; i<m; i++)
		{
			int u = reader.nextInt()-1;
			int v = reader.nextInt()-1;
			
			graph[u].nodes.add(v);
			//revGraph[v].nodes.add(u);
		}
		
		dfs1(s);
		ArrayList<Pair> pairs = new ArrayList<>();
		
		for (int i=0; i<n; i++)
		{
			count = 0;
			Arrays.fill(visit, false);
			
			if (!good[i])
			{
				dfs2(i);
				
				Pair temp = new Pair();
				temp.cnt = count;
				temp.node = i;
				
				pairs.add(temp);
			}
		}
		
		Collections.sort(pairs);
		for (Pair p : pairs)
		{	
			if (!good[p.node])
			{
				ans++;
				dfs1(p.node);
			}
		}
		
		writer.println(ans);
		writer.close();
	}
	
	static void dfs1 (int s)
	{
		good[s] = true;
		
		for (Integer v : graph[s].nodes)
		{
			if (!good[v])
				dfs1(v);
		}
	}
	
	static void dfs2 (int s)
	{
		visit[s] = true;
		count++;
		
		for (Integer v : graph[s].nodes)
		{
			if (!(visit[v] || good[v]))
				dfs2(v);
		}
	}
	
	static class FastReader
	{
		BufferedReader br;
		StringTokenizer st;

		public FastReader()
		{
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next()
		{
			while (st == null || !st.hasMoreElements())
			{
				try
				{
					st = new StringTokenizer(br.readLine());
				}
				catch (IOException e)
				{
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt()
		{
			return Integer.parseInt(next());
		}

		long nextLong()
		{
			return Long.parseLong(next());
		}

		double nextDouble()
		{
			return Double.parseDouble(next());
		}

		String nextLine()
		{
			String str = "";
			try
			{
				str = br.readLine();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
			return str;
		}
	}
}

class MyList1
{
	ArrayList<Integer> nodes = new ArrayList<>();
}

class Pair implements Comparable<Pair>
{
	int cnt;
	int node;
	
	public int compareTo (Pair temp)
	{
		return Integer.compare(temp.cnt, this.cnt);
	}
	
}