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.
/*input
5 4 5
1 2
2 3
3 4
4 1

*/
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
public class Main {
   InputStream is;
	PrintWriter out;
	String INPUT = ""; 
//class Declaration

static class pair implements Comparable<pair>{
    int x,y;
    pair (int i,int j)
    { x=i; y=j;}
    public String toString(){ return x+" "+y;}
    public int compareTo(pair p){
        if(this.x!=p.x) { return this.x-p.x;}
        else { return this.y-p.y;}
    }
    public boolean equals(pair x){ return (x.x==this.x&&x.y==this.y);}
}

ArrayList<ArrayList<Integer>> g;
boolean vis[];
boolean tvis[];
void solve(){ 
	int n=ni(),m=ni(),s=ni();
	g=new ArrayList<>();vis=new boolean[n+1];
	for(int i=0;i<=n;++i) g.add(new ArrayList<>());
	for(int i=0;i<m;++i){
		int x=ni(),y=ni();
		g.get(x).add(y);
		//pn(g);
	}
	//pn(g);
	if(m==0) pn(n-1);
	else{
	int ans=0;
	dfs(s,-1);

ArrayList<pair> al=new ArrayList<>();
for(int i=1;i<=n;++i){
		tvis=new boolean[n+1];
		int cnt=tdfs(i,-1);
		if(cnt>0){
			al.add(new pair(cnt,i));
		}
}
Collections.sort(al,Collections.reverseOrder());

for(pair p:al){
	int id=p.y;
	int cnt=dfs(id,-1);
	if(cnt>0) ans++;
}



pn(ans);

}

}
int dfs(int s,int p){
	if(vis[s]) return 0;
	vis[s]=true;
	int cnt=1;
	ArrayList<Integer> adj=g.get(s);
	for(int x:adj){
		if(x==p) continue;
		cnt+=(dfs(x,s));
	}
	return cnt;
}
int tdfs(int s,int p){
	if(vis[s]||tvis[s]) return 0;
	tvis[s]=true;
	int cnt=1;
	ArrayList<Integer> adj=g.get(s);
	for(int x:adj){
		if(x==p) continue;
		cnt+=(tdfs(x,s));
	}
	return cnt;
}
int min(int[] arr)
{
    int min=Integer.MAX_VALUE;
    for(int i=0;i<arr.length;++i)
    {
        if(min>arr[i]) min=arr[i];
    }
    return min;
}
int max(int[] arr)
{
    int max=Integer.MIN_VALUE;
    for(int i=0;i<arr.length;++i)
    {
        if(max<arr[i]) max=arr[i];
    }
    return max;
}
static int gcd(int x,int y)
{
  if(y==0) return x;
  return gcd(y,x%y);
}
static long nCr(long n,long rc)
{
 long r=Math.min(rc,n-rc);
 long ans=1;
 for(int i=1,j=(int)n;i<=r;++i,--j)
 {
   ans=(ans*(long)j)/((long)i);
 }
  return ans;
  
}

void run() throws Exception
{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
}
	
	
	public static void main(String[] args) throws Exception { new Main().run(); }
	
//output methods
private void pn(Object o)
{
	out.println(o);
}
private void p(Object o)
{
	out.print(o);
}



//input methods
		private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	

	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
		
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private void tr(Object... o) { if(INPUT.length() > 0)System.out.println(Arrays.deepToString(o)); }
}
