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 sun.misc.Queue;

import java.io.*;
import java.util.*;


public class Main {


    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));
        /*
        int n      = sc.nextInt();        // read input as integer
        long k     = sc.nextLong();       // read input as long
        double d   = sc.nextDouble();     // read input as double
        String str = sc.next();           // read input as String
        String s   = sc.nextLine();       // read whole line as String
        */
        int n = sc.nextInt();
        int m = sc.nextInt();
        int s = sc.nextInt();

        Map<Integer, List<Integer>> map = new HashMap<>();
        for (int i = 1; i <= n; i++) {
            map.put(i, new ArrayList<>());
        }
        for (int i = 0; i < m; i++) {
            final int i1 = sc.nextInt();
            final int i2 = sc.nextInt();
            map.get(i1).add(i2);
        }

        int[] v = new int[n + 1];
        dfs(s, map, v, s);
        for (int i = 1; i <= n; i++) {
            if (v[i] == 0) {
                dfs(i, map, v, i);
            }
        }

        Set<Integer> set = new HashSet<>();
        for (int i = 1; i < v.length; i++) {
            if (i != s) {
                set.add(v[i]);
            }
        }
//        System.out.println(set);

        set.remove(s);
        System.out.println(set.size());


        // Stop writing your solution here. -------------------------------------
        out.close();
    }

    private static void dfs(int s, Map<Integer, List<Integer>> map, int[] v, int n) {
        Deque<Integer> q = new ArrayDeque<Integer>();
        q.add(s);
        while (!q.isEmpty()) {
            final Integer poll = q.poll();
            if (v[poll] != n) {
                q.addAll(map.get(poll));
                v[poll] = n;
            }
        }
    }


    static void swap(char[] c, int n) {
        n--;
        for (int i = 0; i <= n / 2; i++) {
            char tmp = c[i];
            c[i] = c[n - i];
            c[n - i] = tmp;
        }
    }


    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;

    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            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;
        }

    }
//--------------------------------------------------------
}