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 java.util.Arrays;
import java.io.IOException;
import java.util.Comparator;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Aman Kumar Singh
 */
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);
        EReachabilityFromTheCapital solver = new EReachabilityFromTheCapital();
        solver.solve(1, in, out);
        out.close();
    }

    static class EReachabilityFromTheCapital {
        PrintWriter out;
        InputReader in;
        ArrayList<Integer>[] digraph;
        boolean[] vis;
        boolean[] vis1;
        int cnt = 0;
        final Comparator<Pair> com = new Comparator<Pair>() {
            public int compare(Pair a, Pair b) {
                if (Integer.compare(b.x, a.x) != 0)
                    return Integer.compare(b.x, a.x);
                else
                    return Integer.compare(a.y, b.y);
            }
        };

        void dfs(int v) {
            vis[v] = true;
            for (int u : digraph[v]) {
                if (!vis[u])
                    dfs(u);
            }
        }

        void dfs1(int v) {
            vis1[v] = true;
            cnt++;
            for (int u : digraph[v]) {
                if (!vis1[u])
                    dfs1(u);
            }
        }

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            this.out = out;
            this.in = in;
            int n = ni();
            int m = ni();
            int s = ni() - 1;
            vis = new boolean[n];
            digraph = new ArrayList[n];
            int i = 0;
            for (i = 0; i < n; i++)
                digraph[i] = new ArrayList<>();
            for (i = 0; i < m; i++) {
                int u = ni() - 1;
                int v = ni() - 1;
                digraph[u].add(v);
            }
            dfs(s);
            int col = 1;
            ArrayList<Integer> ar1 = new ArrayList<>();
            ArrayList<Integer> ar2 = new ArrayList<>();
            for (i = 0; i < n; i++) {
                if (!vis[i]) {
                    cnt = 0;
                    vis1 = new boolean[n];
                    dfs1(i);
                    ar1.add(i);
                    ar2.add(cnt);
                }
            }
            Pair[] hola = new Pair[ar1.size()];
            for (i = 0; i < ar1.size(); i++)
                hola[i] = new Pair(ar2.get(i), ar1.get(i));
            Arrays.sort(hola, com);
            int ans = 0;
            for (i = 0; i < ar1.size(); i++) {
                if (!vis[hola[i].y]) {
                    dfs(hola[i].y);
                    ans++;
                }
            }
            pn(ans);
        }

        int ni() {
            return in.nextInt();
        }

        void pn(Object o) {
            out.println(o);
        }

        class Pair {
            int x;
            int y;

            Pair(int p, int q) {
                x = p;
                y = q;
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1)
                throw new UnknownError();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new UnknownError();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

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

        public String next() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuffer res = new StringBuffer();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));

            return res.toString();
        }

        private boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

    }
}

