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.
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.StringTokenizer;

public class CF999E {
	static ArrayList<Integer>[] adjList;
	static boolean [] visited;
	static boolean [] secondVisited;
	static int reachable;
	static int good;
	public static void main(String[] args) throws IOException {
		FastScanner sc = new FastScanner(System.in);
		PrintWriter pw = new PrintWriter(System.out);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int s = sc.nextInt();
		adjList = new ArrayList[n];
		visited = new boolean[n];
		for (int i = 0; i < n; i++) {
			adjList[i] = new ArrayList<>();
		}
		for (int i = 0; i < m; i++) {
			int from = sc.nextInt();
			int to = sc.nextInt();
			adjList[from-1].add(to-1);
		}
		good = 0;
		dfs(s-1);
		Pair[] bad = new Pair[n-good];
		int idx = 0;
		for (int i = 0; i < n; i++) {
			if(!visited[i]) {
				secondVisited = new boolean[n];
				reachable = 0;
				dfs2(i);
				bad[idx] = new Pair(i, reachable);
				idx++;
			}
		}
		Arrays.sort(bad);
		int cc = 0;
		for (int i = bad.length-1; i >= 0; i--) {
			if(!visited[bad[i].idx]) {
				dfs(bad[i].idx);
				cc++;
			}
		}
		pw.println(cc);
		pw.flush();
	}
	static class Pair implements Comparable<Pair>{
		int idx;
		int c;
		public Pair(int idx, int c) {
			this.idx = idx;
			this.c = c;
		}
		@Override
		public int compareTo(Pair o) {
			return this.c - o.c;
		}
	}
	static void dfs(int i) {
		visited[i] = true;
		good++;
		for (Integer to : adjList[i]) {
			if(!visited[to]) {
				//System.out.println(to);
				dfs(to);
			}
		}
	}
	static void dfs2(int i) {
		secondVisited[i] = true;
		reachable++;
		for (Integer to : adjList[i]) {
			if(!secondVisited[to] && !visited[to])
				dfs2(to);
		}
	}
	static class FastScanner 
	{
		StringTokenizer st;
		BufferedReader br;

		public FastScanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}

		public FastScanner(String s) throws FileNotFoundException{br = new BufferedReader(new FileReader(new File(s)));}

		public String next() throws IOException 
		{
			while (st == null || !st.hasMoreTokens()) 
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

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

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

		public String nextLine() throws IOException {return br.readLine();}

		public double nextDouble() throws IOException
		{
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if(x.charAt(0) == '-')
			{
				neg = true;
				start++;
			}
			for(int i = start; i < x.length(); i++)
				if(x.charAt(i) == '.')
				{
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				}
				else
				{
					sb.append(x.charAt(i));
					if(dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg?-1:1);
		}

		public boolean ready() throws IOException {return br.ready();}

	}
}
