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.OutputStream;
import java.io.PrintWriter;
import java.util.List;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.io.InputStream;

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

    static class EReachabilityFromTheCapital {
        static List<Integer>[] list;
        static int[] visited;

        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int nodes = in.ni(), edges = in.ni(), capital = in.ni();
            list = new List[nodes + 1];
            visited = new int[nodes + 1];
            for (int i = 0; i <= nodes; i++)
                list[i] = new ArrayList<Integer>();

            for (int i = 0; i < edges; i++) {
                int u = in.ni(), v = in.ni();
                list[u].add(v);
            }

            bfs(visited, capital);/* if we move this stmnt to last of loop then it would fail over this testcase
4 7 3
2 1
1 3
3 4
2 3
2 4
1 4
4 2
o/p = 0 req but willl get 1 as we will pass visited as array thus any changes made to it will not be replaced as we are doing in loop
with visit array

2 ---> 1  ----> 3 ----> 4
2 ------------>3
2 --------------------->4
1 <---------------------4

pictorial representation




*/
            for (int i = 1; i <= nodes; i++) {
                int[] visit = new int[nodes + 1];
                if (visited[i] == 0) { /*check for non visited node */
                    bfs(visit, i);
                    int visitysorno = visit[i]; /*if that node turns out to be visited then there is cycle */
                    if (visitysorno == 1) /*remove that cycle by marking sam eelement as not visited */ {
                        visit[i] = 0;
                    }
                    for (int j = 1; j <= nodes; j++) { /*change the visited array according to new visits by this node */
                        if (visit[j] == 1) {
                            visited[j] = 1;
                        }
                    }
//                out.println(visit);
                }
            }
            visited[capital] = 1;
            int count = 0;
            for (int i = 1; i <= nodes; i++) {
                if (visited[i] == 0)
                    count++;
            }
            out.println(count);
        }

        private void bfs(int[] visit, int node) {
            for (int i = 0; i < list[node].size(); i++) {
                int ele = list[node].get(i);
                if (visit[ele] == 0) {
                    visit[ele] = 1;
                    bfs(visit, ele);
                }
            }
        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void close() {
            writer.close();
        }

        public void println(int i) {
            writer.println(i);
        }

    }

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

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

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

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

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

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

        }

    }
}

