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.io.FilterInputStream;
import java.io.BufferedInputStream;
import java.util.Comparator;
import java.util.Collections;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Jenish
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        ScanReader in = new ScanReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        E490 solver = new E490();
        solver.solve(1, in, out);
        out.close();
    }

    static class E490 {
        ArrayList<Integer>[] arrayList;
        boolean[] visited;
        boolean[] visited2;
        int c = 0;

        public void solve(int testNumber, ScanReader in, PrintWriter out) {
            int n = in.scanInt();
            int m = in.scanInt();
            int s = in.scanInt();
            arrayList = new ArrayList[n + 1];
            int incoming[] = new int[n + 1];
            for (int i = 0; i <= n; i++) {
                arrayList[i] = new ArrayList<>();
            }
            for (int i = 0; i < m; i++) {
                int u = in.scanInt();
                int v = in.scanInt();
                arrayList[u].add(v);
                incoming[v]++;
            }
            visited = new boolean[n + 1];
            DFS(s);
            long ans = 0;
            ArrayList<pair> arrayList = new ArrayList<>();
            for (int i = 1; i <= n; i++) {
                visited2 = new boolean[n + 1];
                c = 0;
                DFS2(i);
                arrayList.add(new pair(i, c));
            }

            Collections.sort(arrayList, new Comparator<pair>() {
                public int compare(pair o1, pair o2) {
                    return o2.count - o1.count;
                }
            });


            for (int i = 0; i < arrayList.size(); i++) {
                int t = arrayList.get(i).index;
                if (!visited[t]) {
                    DFS(t);
                    ans++;
                }
            }

            out.println(ans);
        }

        void DFS(int s) {
            visited[s] = true;
            for (int i = 0; i < arrayList[s].size(); i++) {
                int t = arrayList[s].get(i);
                if (!visited[t]) {
                    DFS(t);
                }
            }
        }

        void DFS2(int s) {
            visited2[s] = true;
            c++;
            for (int i = 0; i < arrayList[s].size(); i++) {
                int t = arrayList[s].get(i);
                if (!visited2[t]) {
                    DFS2(t);
                }
            }
        }

        class pair {
            int index;
            int count;

            public pair(int index, int count) {
                this.index = index;
                this.count = count;
            }

        }

    }

    static class ScanReader {
        private byte[] buf = new byte[4 * 1024];
        private int INDEX;
        private BufferedInputStream in;
        private int TOTAL;

        public ScanReader(InputStream inputStream) {
            in = new BufferedInputStream(inputStream);
        }

        private int scan() {
            if (INDEX >= TOTAL) {
                INDEX = 0;
                try {
                    TOTAL = in.read(buf);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (TOTAL <= 0) return -1;
            }
            return buf[INDEX++];
        }

        public int scanInt() {
            int I = 0;
            int n = scan();
            while (isWhiteSpace(n)) n = scan();
            int neg = 1;
            if (n == '-') {
                neg = -1;
                n = scan();
            }
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    I *= 10;
                    I += n - '0';
                    n = scan();
                }
            }
            return neg * I;
        }

        private boolean isWhiteSpace(int n) {
            if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1) return true;
            else return false;
        }

    }
}

