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.lang.reflect.Array;
        import java.util.*;
        import java.io.*;

public class Main {
    public static void main(String args[]) {
        InputReader in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out);
        Task solver = new Task();
        solver.solve(in, out);
        out.close();
    }

    static class Task {
        ArrayList<Integer>[] g;
        boolean[] vis, used;
        int cnt;

        public void solve(InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int s = in.nextInt();
            --s;
            vis = new boolean[n];
            used = new boolean[n];
            g = new ArrayList[n];
            for (int i = 0; i < n; ++i) g[i] = new ArrayList<>();
            while (m-->0){
                int x = in.nextInt();
                int y = in.nextInt();
                --x;
                --y;
                g[x].add(y);
            }
            dfs1(s);
            ArrayList<Task.Pair> t = new ArrayList<Task.Pair>();
            for (int i = 0; i < n; ++i) {
                if (!vis[i]) {
                    cnt = 0;
                    Arrays.fill(used, false);
                    dfs2(i);
                    t.add(new Task.Pair(cnt, i));
                }
            }
            Collections.sort(t, Task.Pair::comp);
            int ans = 0;
            for (Task.Pair x : t) {
                if (!vis[x.second]) {
                    ++ans;
                    dfs1(x.second);
                }
            }
            out.println(ans);
        }

        private void dfs1(int v) {
            vis[v] = true;
            for (int to : g[v]) if (!vis[to]) dfs1(to);
        }

        private void dfs2(int v) {
            used[v] = true;
            ++cnt;
            for (int to : g[v]) if (!used[to]) dfs2(to);
        }

        static class Pair {
            int first;
            int second;

            public Pair(int l, int r){
                first = l;
                second = r;
            }

            public int comp(Task.Pair o) {
                return first < o.first ? 1 : first == o.first ? 0 : -1;
            }
        }
    }

    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());
        }
    }
}