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.util.*;
import java.lang.Math;

public final class ProblemE {
    static class Vertex {
        int vi;
        int count;
        public Vertex(int i, int count) {
            this.vi = i;
            this.count = count;
        }

        public String toString() {
            return vi +" count:"+ count;
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int s = sc.nextInt() - 1;

        Graph g = new Graph(n);

        for (int i = 0 ; i < m ; i++) {
            g.addEdge(sc.nextInt() - 1, sc.nextInt() - 1);
        }

        //System.out.println(Arrays.toString(g.adj));
        boolean[] reach = new boolean[n];

        markReachable(g, s, reach);


        //System.out.println(Arrays.toString(reach));
       // int count = 0;

        int[] unreachCount = getUnreachCount(reach, g);
        Vertex[] vertices = new Vertex[n];
        for (int i = 0 ; i < n ; i++) {
            vertices[i] = new Vertex(i, unreachCount[i]);
        }
        Arrays.sort(vertices,new Comparator<Vertex>() {
            public int compare(Vertex a, Vertex b){
                return b.count - a.count;
            }
        });
        //System.out.println(Arrays.toString(unreachCount));

        // Caclulate answer
        int ans = 0;

        for (int i = 0 ; i < n ; i++) {
            Vertex v = vertices[i];

            if (reach[v.vi]) {
                continue;
            }
            if (v.count == 0) {
                continue;
            }

            // Bad vertex
            markReach(v.vi, g, reach);
            ans += 1;
        }
        //System.out.println(Arrays.toString(vertices));
        System.out.println(ans);

    }

    static void markReach(int v, Graph g, boolean[] reach) {
        if (reach[v]) {
            return;
        }
        reach[v] = true;
        for (Edge e : g.adj[v]) {
            if (!reach[e.to]) {
                markReach(e.to, g, reach);
            }
        }
    }

    static int[] getUnreachCount(boolean[] reach, Graph g) {
        int[] unreachCount  = new int[g.V];
        for (int i = 0; i < g.V ; i++) {
            if (reach[i]) {
                continue;
            }
            unreachCount[i] = dfsUnreachCount(g, i, reach, new boolean[g.V]);
        }
        return unreachCount;
    }

    static int dfsUnreachCount(Graph g, int n, boolean[] reach, boolean[] visited) {
        visited[n] = true;
        if (reach[n]) {
            return 0;
        }
        int count = 1;
        for (Edge e : g.adj[n]) {
            if (!reach[e.to] && !visited[e.to]) {
                count += dfsUnreachCount(g, e.to, reach, visited);
            }
        }
        return count;
    }


    static void markReachable(Graph g, int source, boolean[] reach) {
        if (reach[source]) {
            return;
        }
        reach[source] = true;
        for (Edge e : g.adj[source]) {
            if (!reach[e.to]) {
                markReachable(g, e.to, reach);
            }
        }
    }

    static class Graph {
        int V;
        LinkedList<Edge>[] adj;

        public Graph(int v){
            this.V = v;
            this.adj = new LinkedList[v];
            for (int i = 0 ; i < v ; i++) {
                this.adj[i] = new LinkedList<Edge>();
            }
        }

        public void addEdge(int from, int to) {
            this.adj[from].add(new Edge(from, to));
        }
    }

    static class Edge {
        int from;
        int to;

        public Edge(int from, int to) {
            this.from = from;
            this.to = to;
        }

        public String toString() {
            return from +"-"+to;
        }
    }




}
