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.*;
import java.util.*;

public class Main {
    private static Scanner sc;
    private static Printer pr;
    static long aLong=(long )1e9+7;
    static long Mod=998244353;
    static ArrayList<Integer>[]list;
    static TreeSet<Integer>ver;
    static boolean[]vis;
    static boolean[]visBad;
    static int cnt=0;
    private static void solve() throws IOException {
        //in the name of god
        // you are anything and we are nothing
        //God,i am so tired . I have no one but you
        int n=sc.nextInt(),m=sc.nextInt(),s=sc.nextInt();
        list=new ArrayList[n+1];
        vis=new boolean[n+1];
        visBad=new boolean[n+1];
        ver=new TreeSet<>();
        for (int i=1;i<=n;++i)
            list[i]=new ArrayList<>();
        for (int i=1;i<=m;++i) {
            int u = sc.nextInt(), v = sc.nextInt();
            list[u].add(v);
        }
        dfs(s);
        PriorityQueue<BadComponent>priorityQueue=new PriorityQueue<>(new Comparator<BadComponent>() {
            @Override
            public int compare(BadComponent o1, BadComponent o2) {
                if (o1.cnt>o2.cnt)return -1;
                return 1;
            }
        });
        for (int i=1;i<=n;++i){
            if (!ver.contains(i)){
                Arrays.fill(visBad,false);
                dfs_1(i);
                priorityQueue.add(new BadComponent(i,cnt));
                cnt=0;
            }
        }
        int ans=0;
        while (!priorityQueue.isEmpty()){
            BadComponent b=priorityQueue.poll();
            if (!vis[b.id]){
                dfs_2(b.id);
                ++ans;
            }
        }
        pr.println(ans);
    }
    static class BadComponent{
        int id,cnt;
        public BadComponent(int id, int cnt) {
            this.id = id;
            this.cnt = cnt;
        }
    }
    public  static void dfs(int src){
        vis[src]=true;
        ver.add(src);
        for (int v:list[src]){
            if (!vis[v]){
                dfs(v);
            }
        }
    }
    public static void dfs_1(int src){
        visBad[src]=true;
        ++cnt;
        for (int v:list[src]){
            if (!visBad[v]){
                dfs_1(v);
            }
        }
    }
    public static void dfs_2(int src){
        vis[src]=true;
        for (int v:list[src]){
            if (!vis[v]){
                dfs(v);
            }
        }
    }
    public static int[] radixSort(int[] f) {
        int[] to = new int[f.length];
        {
            int[] b = new int[65537];
            for (int i = 0; i < f.length; i++) b[1 + (f[i] & 0xffff)]++;
            for (int i = 1; i <= 65536; i++) b[i] += b[i - 1];
            for (int i = 0; i < f.length; i++) to[b[f[i] & 0xffff]++] = f[i];
            int[] d = f;
            f = to;
            to = d;
        }
        {
            int[] b = new int[65537];
            for (int i = 0; i < f.length; i++) b[1 + (f[i] >>> 16)]++;
            for (int i = 1; i <= 65536; i++) b[i] += b[i - 1];
            for (int i = 0; i < f.length; i++) to[b[f[i] >>> 16]++] = f[i];
            int[] d = f;
            f = to;
            to = d;
        }
        return f;
    }
    public static long []primeFactor(int n){
        long []prime=new long[n+1];
        prime[1]=1;
        for (int i=2;i<=n;i++)
            prime[i]=((i&1)==0)?2:i;
        for (int i=3;i*i<=n;i++){
            if (prime[i]==i){
                for (int j=i*i;j<=n;j+=i){
                    if (prime[j]==j)
                        prime[j]=i;
                }
            }
        }
        return prime;
    }
    public static long gcd(long a,long b) {
        if (a == 0) return b;
        return gcd(b % a, a);
    }
    public static void main(String[] args) throws IOException {
        sc = new Scanner(System.in);
        pr = new Printer(System.out);
        solve();

        pr.close();
        // sc.close();
    }
    private static class Scanner {
        BufferedReader br;

        Scanner (InputStream in) {
            br = new BufferedReader(new InputStreamReader(in));
        }

        private boolean isPrintable(int ch) {
            return ch >= '!' && ch <= '~';
        }

        private boolean isCRLF(int ch) {
            return ch == '\n' || ch == '\r' || ch == -1;
        }

        private int nextPrintable() {
            try {
                int ch;
                while (!isPrintable(ch = br.read())) {
                    if (ch == -1) {
                        throw new NoSuchElementException();
                    }
                }

                return ch;
            } catch (IOException e) {
                throw new NoSuchElementException();
            }
        }

        String next() {
            try {
                int ch = nextPrintable();
                StringBuilder sb = new StringBuilder();
                do {
                    sb.appendCodePoint(ch);
                } while (isPrintable(ch = br.read()));

                return sb.toString();
            } catch (IOException e) {
                throw new NoSuchElementException();
            }
        }

        int nextInt() {
            try {
                // parseInt from Integer.parseInt()
                boolean negative = false;
                int res = 0;
                int limit = -Integer.MAX_VALUE;
                int radix = 10;

                int fc = nextPrintable();
                if (fc < '0') {
                    if (fc == '-') {
                        negative = true;
                        limit = Integer.MIN_VALUE;
                    } else if (fc != '+') {
                        throw new NumberFormatException();
                    }
                    fc = br.read();
                }
                int multmin = limit / radix;

                int ch = fc;
                do {
                    int digit = ch - '0';
                    if (digit < 0 || digit >= radix) {
                        throw new NumberFormatException();
                    }
                    if (res < multmin) {
                        throw new NumberFormatException();
                    }
                    res *= radix;
                    if (res < limit + digit) {
                        throw new NumberFormatException();
                    }
                    res -= digit;

                } while (isPrintable(ch = br.read()));

                return negative ? res : -res;
            } catch (IOException e) {
                throw new NoSuchElementException();
            }
        }

        long nextLong() {
            try {
                // parseLong from Long.parseLong()
                boolean negative = false;
                long res = 0;
                long limit = -Long.MAX_VALUE;
                int radix = 10;

                int fc = nextPrintable();
                if (fc < '0') {
                    if (fc == '-') {
                        negative = true;
                        limit = Long.MIN_VALUE;
                    } else if (fc != '+') {
                        throw new NumberFormatException();
                    }
                    fc = br.read();
                }
                long multmin = limit / radix;

                int ch = fc;
                do {
                    int digit = ch - '0';
                    if (digit < 0 || digit >= radix) {
                        throw new NumberFormatException();
                    }
                    if (res < multmin) {
                        throw new NumberFormatException();
                    }
                    res *= radix;
                    if (res < limit + digit) {
                        throw new NumberFormatException();
                    }
                    res -= digit;

                } while (isPrintable(ch = br.read()));

                return negative ? res : -res;
            } catch (IOException e) {
                throw new NoSuchElementException();
            }
        }

        float nextFloat() {
            return Float.parseFloat(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            try {
                int ch;
                while (isCRLF(ch = br.read())) {
                    if (ch == -1) {
                        throw new NoSuchElementException();
                    }
                }
                StringBuilder sb = new StringBuilder();
                do {
                    sb.appendCodePoint(ch);
                } while (!isCRLF(ch = br.read()));

                return sb.toString();
            } catch (IOException e) {
                throw new NoSuchElementException();
            }
        }

        void close() {
            try {
                br.close();
            } catch (IOException e) {
//				throw new NoSuchElementException();
            }
        }
    }
    private static class Printer extends PrintWriter {
        Printer(PrintStream out) {
            super(out);
        }
    }
}