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.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.StringTokenizer;

//http://codeforces.com/contest/994/problem/A
public class Main2 {

	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		XeniaAndBitOperations solver = new XeniaAndBitOperations();
		// int test = in.nextInt();
		// while (test-- > 0)
		solver.solve(1, in, out);
		out.close();
	}

	static class XeniaAndBitOperations {

		boolean vis[];
		ArrayList<Integer> g[];
		boolean used[];
		int count;

		public static class Pair implements Comparable<Pair> {
			@Override
			public String toString() {
				return "Pair [ver=" + ver + ", c=" + c + "]";
			}

			int ver;
			int c;

			public Pair(int ver, int c) {
				this.ver = ver;
				this.c = c;
			}

			@Override
			public int compareTo(Pair o) {
				return (o.c - this.c);
			}
		}

		public void solve(int testNumber, InputReader in, PrintWriter out) {

			int n = in.nextInt();
			int m = in.nextInt();
			int s = in.nextInt();

			vis = new boolean[n];

			g = new ArrayList[n];
			for (int i = 0; i < n; i++)
				g[i] = new ArrayList<>();

			for (int i = 0; i < m; i++) {
				int x = in.nextInt();
				int y = in.nextInt();
				x--;
				y--;
				g[x].add(y);
			}

			s--;

			dfs1(s);

			ArrayList<Pair> list = new ArrayList<>();
			for (int i = 0; i < n; i++) {
				if (!vis[i]) {
					Pair pair = new Pair(i, 0);
					list.add(pair);
				}
			}

			for (Pair p : list) {
				count = 0;
				used = new boolean[n];
				dfs2(p.ver);
				p.c = count;
			}

			Collections.sort(list);

			int ans = 0;
			for (Pair p : list) {
				if (!vis[p.ver]) {
					dfs1(p.ver);
					ans++;
				}
			}

			out.write(ans + "\n");
		}

		private void dfs1(int s) {
			vis[s] = true;
			for (Integer adj : g[s]) {
				if (!vis[adj])
					dfs1(adj);
			}
		}

		private void dfs2(int s) {
			used[s] = true;
			count++;
			for (Integer adj : g[s]) {
				if (!used[adj])
					dfs2(adj);
			}
		}

	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

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

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

	}
}