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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class A {
	public static class Pair {
		int first;
		int second;

		Pair(int first, int second) {
			this.first = first;
			this.second = second;
		}

		public int getFirst() {
			return first;
		}

		public void setFirst(int first) {
			this.first = first;
		}

		public int getSecond() {
			return second;
		}

		public void setSecond(int second) {
			this.second = second;
		}

	}

	public static class ReportComparator implements Comparator<Pair> {
		public int compare(Pair r1, Pair r2) {
			int f1 = r1.getFirst();
			int f2 = r2.getFirst();
			if (f1 > f2)
				return -1;
			else if (f1 == f2)
				return 0;
			else
				return 1;
		}
	}

	static int[] vis = new int[200005];
	static int[] vis2 = new int[2000005];
	static int cnt = 0;

	static List<Pair> list = new ArrayList<>();
	@SuppressWarnings("unchecked")
	static List<Integer>[] v = new ArrayList[200005];

	public static void main(String[] args) {

		for (int i = 0; i < 200005; i++)
			v[i] = new ArrayList<>();

		 FastReader tt=new FastReader();
		int n = tt.nextInt();
		int m = tt.nextInt();
		int s = tt.nextInt();
		s--;
		for (int i = 0; i < m; i++) {
			int a = tt.nextInt();
			int b = tt.nextInt();
			a--;
			b--;
			v[a].add(b);

		}

		dfs(s);
		int t = 0;
		int cc=2;

		// Pair pp = new Pair(0, 0);

		for (int i = 0; i < n; i++) {

			if (vis[i] == 0) {
				cnt = 0;

				//for (int j = 0; j < n; j++)
				//	vis2[j] = 0;
				
				cc++;

				dfs2(i, cc);
				list.add(new Pair(cnt, i));
			}

		}
		//Collections.sort(list, new ReportComparator());
		
		Collections.sort(list, new Comparator<Pair>() {
			@Override
			public int compare(Pair o1, Pair o2) {
				return -o1.getFirst() + o2.getFirst();
			}
		});
		int ans = 0;

		for (Pair ll : list) {
			// System.out.println(ll.first + " " + ll.second);

			int se = ll.second;
			if (vis[se] == 0) {
				ans++;
				dfs(se);
			}
		}
		System.out.println(ans);

	}

	public static void dfs2(int s, int t) {
		// TODO Auto-generated method stub
		vis2[s] = t;
		int len = v[s].size();
		cnt++;
		for (int i = 0; i < len; i++) {
			int val = v[s].get(i);
			if (vis2[val] == t) continue;
			else{
				dfs2(val, t);
			}
		}

	}

	public static void dfs(int s) {

		// TODO Auto-generated method stub

		vis[s] = 1;
		int len = v[s].size();
		for (int i = 0; i < len; i++) {
			int val = v[s].get(i);
			if (vis[val] == 0) {
				dfs(val);
			}
		}

	}
	
	 static class FastReader
	    {
	        BufferedReader br;
	        StringTokenizer st;
	 
	        public FastReader()
	        {
	            br = new BufferedReader(new
	                     InputStreamReader(System.in));
	        }
	 
	        String next()
	        {
	            while (st == null || !st.hasMoreElements())
	            {
	                try
	                {
	                    st = new StringTokenizer(br.readLine());
	                }
	                catch (IOException  e)
	                {
	                    e.printStackTrace();
	                }
	            }
	            return st.nextToken();
	        }
	 
	        int nextInt()
	        {
	            return Integer.parseInt(next());
	        }
	 
	        long nextLong()
	        {
	            return Long.parseLong(next());
	        }
	 
	        double nextDouble()
	        {
	            return Double.parseDouble(next());
	        }
	 
	        String nextLine()
	        {
	            String str = "";
	            try
	            {
	                str = br.readLine();
	            }
	            catch (IOException e)
	            {
	                e.printStackTrace();
	            }
	            return str;
	        }
	    }

}
