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.math.*;
import java.util.*;


/**
 *
 * @author Saju
 *
 */

public class Main {

    private static int dx[] = { 1, 0, -1, 0 };
    private static int dy[] = { 0, -1, 0, 1 };

    private static final long INF = Long.MAX_VALUE;
    private static final int INT_INF = Integer.MAX_VALUE;
    private static final long NEG_INF = Long.MIN_VALUE;
    private static final int NEG_INT_INF = Integer.MIN_VALUE;
    private static final double EPSILON = 1e-10;

    private static final int MAX = 107;
    
    private static final long MOD = 1000000007;

    private static final int MAXN = 100007;
    private static final int MAXA = 10000009;
    private static final int MAXLOG = 22;

	public static void main(String[] args) throws IOException {

		InputReader in = new InputReader(System.in);
//		Scanner in = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);

//         InputReader in = new InputReader(new FileInputStream("src/test.in"));
//         PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("src/test.out")));

		
		
/*




*/
	
		int n = in.nextInt();
		int m = in.nextInt();
		int src = in.nextInt() - 1;
		List<Integer>adj[] = new ArrayList[n];
		for(int i = 0; i < n; i++) {
			adj[i] = new ArrayList<Integer>();
		}
		
		for(int i = 0; i < m; i++) {
			int u = in.nextInt();
			int v = in.nextInt();
			u--;
			v--;
			adj[u].add(v);
//			adj[v].add(u);
		}
		
		boolean[] marked = new boolean[n];
		dfs(src, -1, adj, marked);
		List<Pair> pairs = new ArrayList<>();
		for(int i = 0; i < n; i++) {
			if(!marked[i]) {
				cnt = 0;
				boolean[] marked1 = new boolean[n];
				 dfs1(i, -1, adj, marked, marked1);
				 pairs.add(new Pair(i, cnt));
//				 System.out.println(i + " " + cnt);
			}
		}
		
		Collections.sort(pairs, new Comparator<Pair>() {

			@Override
			public int compare(Pair o1, Pair o2) {
				int val = o2.b - o1.b;
				return val;
			}
		});
		cnt = 0;
		for(Pair p : pairs) {
			if(!marked[p.a]) {
				cnt++;
				dfs(p.a, -1, adj, marked);
			}
		}
		out.println(cnt);
		
		
		in.close();
		out.flush();
		out.close();
		System.exit(0);
	}

	static int cnt = 0;
	private static void dfs1(int u, int p, List<Integer>[] adj, boolean[] marked, boolean[] marked1) {
		if(!marked[u]) {
			cnt++;
		}
		marked1[u] = true;
		for(int v : adj[u]) {
			if(v != p && !marked1[v]) {
				dfs1(v, u, adj, marked, marked1);
			}
		}
	}


	private static void dfs(int u, int p, List<Integer>[] adj, boolean[] marked) {
		marked[u] = true;
		
		for(int v : adj[u]) {
			if(v != p && !marked[v]) {
				dfs(v, u, adj, marked);
			}
		}
	}


	private static class Pair{
		int a;
		int b;
		Pair(int a, int b){
			this.a = a;
			this.b = b;
		}
	}
	
	private static boolean isPalindrome(String str) {
		StringBuilder sb = new StringBuilder();
		sb.append(str);
		String str1 = sb.reverse().toString();
		return str.equals(str1);
	}
	
	private static String getBinaryStr(int n, int j) {
		String str = Integer.toBinaryString(n);
		int k = str.length();
		for (int i = 1; i <= j - k; i++) {
			str = "0" + str;
		}

		return str;
	}
	
	private static long bigMod(long n, long k, long m) {

        long ans = 1;
        while (k > 0) {
            if ((k & 1) == 1) {
                ans = (ans * n) % m;
            }
            n = (n * n) % m;
            k >>= 1;
        }
        return ans;
    }
    
	private static long ceil(long n, long x) {
		long div = n / x;
        if(div * x != n) {
            div++;
        }
        return div;
	}
	
    private static int ceil(int n, int x) {
        int div = n / x;
        if(div * x != n) {
            div++;
        }
        return div;
    }

    private static class Point {
        double x;
        double y;

        Point(double x, double y) {
            this.x = x;
            this.y = y;
        }

        double getDistance(Point p2) {
            Point p1 = this;
            double dx = p1.x - p2.x;
            double dy = p1.y - p2.y;

            return Math.sqrt((dx * dx) + (dy * dy));
        }
    }

    private static int abs(int x) {
        if (x < 0) {
            return -x;
        }
        return x;
    }

    private static long abs(long x) {
        if(x < 0) {
            return -x;
        }
        return x;
    }

    private static int lcm(int a, int b) {
        return (a * b) / gcd(a, b);
    }

    private static int gcd(int a, int b) {
        if (a == 0)
            return b;
        return gcd(b % a, a);
    }

    private static int log(long x, int base) {
        return (int) (Math.log(x) / Math.log(base));
    }

    private static long min(long a, long b) {
        if (a < b) {
            return a;
        }
        return b;
    }

    private static int min(int a, int b) {
        if (a < b) {
            return a;
        }
        return b;
    }

    private static long max(long a, long b) {
        if (a < b) {
            return b;
        }
        return a;
    }

    private static int max(int a, int b) {
        if (a < b) {
            return b;
        }
        return a;
    }

    private static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
            tokenizer = null;
        }

        public String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());

                }
            } catch (IOException e) {
                return null;
            }
            return tokenizer.nextToken();
        }

        public String nextLine() {
            String line = null;
            try {
                tokenizer = null;
                line = reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            return line;
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

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

        public long nextLong() {
            return Long.parseLong(next());
        }

        public boolean hasNext() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (Exception e) {
                return false;
            }
            return true;
        }
        public void close() {
        	try {
        		if(reader != null) {
        			reader.close();
        		}
        	}
        	catch(Exception e) {
        		
        	}
        	
        	
        }
    }

}

 	 					   	    		 	   			  		