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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

import javafx.util.Pair;

import java.util.Arrays;
import java.util.PriorityQueue;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.AbstractCollection;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskE solver = new TaskE();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskE {
        boolean[] hasPath;
        boolean[] used;
        ArrayList<ArrayList<Integer>> neig;

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int s = in.nextInt();
            neig = new ArrayList<>();
            for (int i = 0; i <= n; i++) {
                neig.add(new ArrayList<>());
            }
            for (int i = 0; i < m; i++) {
                int u = in.nextInt();
                int v = in.nextInt();
                neig.get(u).add(v);
            }
            hasPath = new boolean[n + 1];
            used = new boolean[n + 1];
            used[s] = true;
            hasPath[s] = true;
            dfs(s);
            PriorityQueue<Pair<Integer, Integer>> subSize = new PriorityQueue<>(
                    (Pair<Integer, Integer> a, Pair<Integer, Integer> b) -> b.getKey() - a.getKey());
            for (int i = 1; i <= n; i++) {
                if (!hasPath[i]) {
                    Arrays.fill(used, false);
                    used[i] = true;
                    subSize.offer(new Pair<>(dfs2(i), i));
                }
            }
            int ans = 0;
            while (!subSize.isEmpty()) {
                Pair<Integer, Integer> cur = subSize.poll();
                if (!hasPath[cur.getValue()]) {
                    Arrays.fill(used, false);
                    used[cur.getValue()] = true;
                    hasPath[cur.getValue()] = true;
                    dfs(cur.getValue());
                    ans++;
                }
            }
            out.println(ans);
        }

        void dfs(int node) {
            for (int next : neig.get(node)) {
                if (!used[next]) {
                    used[next] = true;
                    hasPath[next] = true;
                    dfs(next);
                }
            }
        }

        int dfs2(int node) {
            int res = 1;
            for (int next : neig.get(node)) {
                if (!used[next] && !hasPath[next]) {
                    used[next] = true;
                    res += dfs2(next);
                }
            }
            return res;
        }

    }

    static class InputReader {
        private BufferedReader reader;
        private StringTokenizer stt;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
        }

        public String nextLine() {
            try {
                return reader.readLine();
            } catch (IOException e) {
                return null;
            }
        }

        public String next() {
            while (stt == null || !stt.hasMoreTokens()) {
                stt = new StringTokenizer(nextLine());
            }
            return stt.nextToken();
        }

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

    }
}

