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.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.Collections;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
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 {
        ArrayList<Integer>[] graph;
        boolean[] vis;
        boolean[] vis2;

        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int ntc = 1;
//        ntc = in.nextInt();
            while ((ntc--) > 0) {
                int n = in.nextInt();
                int m = in.nextInt();
                int s = in.nextInt();
                graph = new ArrayList[n + 1];
                for (int i = 0; i <= n; i++) {
                    graph[i] = new ArrayList<>();
                }
                vis = new boolean[n + 1];
                vis2 = new boolean[n + 1];
                for (int i = 0; i < m; i++) {
                    int u = in.nextInt();
                    int v = in.nextInt();
                    graph[u].add(v);
                }
                dfs(s);
                ArrayList<_C.Pair<Integer, Integer>> pairs = new ArrayList<>();
                for (int i = 1; i <= n; i++) {
                    if (i == s || vis[i]) continue;
                    vis2 = new boolean[n + 1];
                    int c = dfs2(i);
                    if (c > 0) {
                        pairs.add(new _C.Pair<>(i, c));
                    }
                }
                int ans = 0;
                Collections.sort(pairs, (a, b) -> b.s - a.s);
                for (_C.Pair<Integer, Integer> pair : pairs) {
                    if (!vis[pair.f]) {
                        dfs(pair.f);
                        ans += 1;
                    }
                }
                for (int i = 1; i <= n; i++) {
                    if (!vis[i]) {
                        ans += 1;
                    }
                }
                out.println(ans);
            }
        }

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

        int dfs2(int u) {
            int c = 0;
            vis2[u] = true;
            for (int v : graph[u]) {
                if (!vis2[v] && !vis[v]) {
                    c += (1 + dfs2(v));
                }
            }
            return c;
        }

    }

    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(long i) {
            writer.println(i);
        }

    }

    static class _C {
        static public class Pair<F extends Comparable<F>, S extends Comparable<S>> implements Comparable<_C.Pair<F, S>> {
            public F f;
            public S s;

            public Pair(F f, S s) {
                this.f = f;
                this.s = s;
            }

            public int compareTo(_C.Pair<F, S> o) {
                int t = f.compareTo(o.f);
                if (t == 0) return s.compareTo(o.s);
                return t;
            }

            public int hashCode() {
                return (31 + f.hashCode()) * 31 + s.hashCode();
            }

            public boolean equals(Object o) {
                if (!(o instanceof _C.Pair)) return false;
                if (o == this) return true;
                _C.Pair p = (_C.Pair) o;
                return f.equals(p.f) && s.equals(p.s);
            }

            public String toString() {
                return "{" + f + ", " + s + "}";
            }

        }

    }

    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 nextInt() {
            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);

        }

    }
}

