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 javafx.util.Pair;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;

import static java.lang.Math.*;

public class firstone {

    public static TreeSet<String> hs;
    public static ArrayList<Integer> graph[];
    public static int []a ;
    public static InputReader in;
    public static PrintWriter out;
    public static void main(String[] args) {

        in = new InputReader(System.in);
        out = new PrintWriter(System.out);

        int n = in.nextInt();
        int m = in.nextInt();
        int root = in.nextInt();
        graph = new ArrayList[5011];
        for (int i = 0 ;i<graph.length;i++)
        {
            graph[i] = new ArrayList<>();
        }
        for(int i = 0 ;i<m;i++)
        {
            graph[in.nextInt()].add(in.nextInt());
        }
        rechable(root);
        /*for (int i = 0 ;i<=n;i++)
        {
            out.println(i+" "+reach[i]);
        }
        */
        ArrayList<Pair<Integer,Integer>> subtreenotreach = new ArrayList<>();
        for (int i = 1 ;i<=n;i++)
        {
            count = 0 ;
            Arrays.fill(visit,false);
            if(!reach[i])
            {
                subtree(i);
                //out.println(count+" "+i);
                Pair<Integer,Integer> p = new Pair<>(count,i);
                subtreenotreach.add(p);
            }

        }
        Collections.sort(subtreenotreach, new Comparator<Pair<Integer, Integer>>() {
            @Override
            public int compare(Pair<Integer, Integer> o1, Pair<Integer, Integer> o2) {
                if(o1.getKey()>o2.getKey())
                    return -1;
                else if(o1.getKey()<o2.getKey())
                    return 1;
                else
                    return 0;
            }
        });

        int ans = 0;
        for (Pair<Integer,Integer> p :subtreenotreach){

           // out.println(p.getKey()+" "+p.getValue());
            if(!reach[p.getValue()])
            {
                ans++;
                rechable(p.getValue());
            }
        }
        out.println(ans);






        out.close();

    }
    static boolean reach[] = new boolean[5011];
    static boolean visit[] = new boolean[5011];
    static int count = 0;
    static void rechable(int node)
    {
        reach[node] = true;
        for (int i = 0 ;i<graph[node].size();i++)
        {
            if(!reach[graph[node].get(i)])
            {
                rechable(graph[node].get(i));
            }
        }
    }
    static void subtree(int node)
    {
        visit[node] = true;
        count++;
       // out.println(graph[node].size()+" SIZE");
        for (int i = 0 ;i<graph[node].size();i++)
        {
            if(!(visit[graph[node].get(i)] || reach[graph[node].get(i)]))
            {
                //out.println(graph[node].get(i)+" "+node+" node");
                subtree(graph[node].get(i));
            }
        }
       // out.println(node);
        //return count;

    }





    static class InputReader {

        private InputStream stream;
        private byte[] buf = new byte[8192];
        private int curChar, snumChars;
        private InputReader.SpaceCharFilter filter;

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

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

        public int nextInt() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int[] nextIntArray(int n) {
            int a[] = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        public String readString() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = snext();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

}
