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.BufferedReader;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.text.DateFormatSymbols;
import java.util.*;

public class Main {
    static boolean[] ok, was;
    static int n, m, s, ans = 0;
    static ArrayList<Integer>[] mx;

    static void mainDFS(int i) {
        ok[i] = true;
        for (int j : mx[i]) {
            if (!ok[j])
                mainDFS(j);
        }
    }

    static void dfs(int i) {
        ct++;
        was[i] = true;
        for (int j : mx[i]) {
            if (!was[j])
                dfs(j);
        }
    }

    static int ct = 0;

    public static void main(String args[]) throws Exception {
        init();
        n = nextInt();
        m = nextInt();
        s = nextInt() - 1;
        mx = new ArrayList[n];
        ok = new boolean[n];
        for (int i = 0; i < n; i++) {
            mx[i] = new ArrayList<>();
        }
        for (int i = 0; i < m; i++) {
            int from = nextInt() - 1,
                    to = nextInt() - 1;
            mx[from].add(to);
        }
        mainDFS(s);
        was = new boolean[n];
        ArrayList<Pair<Integer, Integer>> al = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            ct = 0;
            was = new boolean[n];
            if (!ok[i])
                dfs(i);
            al.add(new Pair<>(ct, i));
        }
        al.sort(new Comparator<Pair<Integer, Integer>>() {
            public int compare(Pair<Integer, Integer> o1,
                               Pair<Integer, Integer> o2) {
                return -Integer.compare(o1.getKey(), o2.getKey());
            }
        });
        for (Pair<Integer, Integer> p : al){
            if (!ok[p.getValue()]) {
                mainDFS(p.getValue());
                ans++;
            }
        }
        out.println(ans);
        out.close();
    }

    static BufferedReader scan;
    static PrintWriter out;
    static StringTokenizer st;

    static void init() {
        scan = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
    }

    static void init(String name1, String name2) throws Exception {
        try {
            scan = new BufferedReader(new FileReader(name1));
            out = new PrintWriter(name2);
        } catch (Exception e) {
            scan = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        }
    }

    static String next() throws Exception {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(scan.readLine());
        return st.nextToken();
    }

    static int nextInt() throws Exception {
        return Integer.parseInt(next());
    }

    static long nextLong() throws Exception {
        return Long.parseLong(next());
    }
}