import java.util.*;
import java.io.*;
 
public class Main {
    static List<Integer>[] graph;
    static int[][] dp;
 
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] firstLine = br.readLine().split(" ");
        int n = Integer.parseInt(firstLine[0]);
        int s = Integer.parseInt(firstLine[1]);
 
        graph = new ArrayList[n + 1];
        for (int i = 1; i <= n; i++) {
            graph[i] = new ArrayList<>();
        }
 
        for (int i = 0; i < n - 1; i++) {
            String[] edge = br.readLine().split(" ");
            int u = Integer.parseInt(edge[0]);
            int v = Integer.parseInt(edge[1]);
            graph[u].add(v);
            graph[v].add(u);
        }
 
        dp = new int[n + 1][2];
        dfs(s, 0);
 
        System.out.println(dp[s][1]);
    }
 
    static void dfs(int node, int parent) {
        dp[node][0] = 0;  // 不选当前节点
        dp[node][1] = 1;  // 选当前节点
 
        for (int neighbor : graph[node]) {
            if (neighbor == parent) continue;
 
            dfs(neighbor, node);
 
            // 不选当前节点时，子节点可选可不选
            dp[node][0] += Math.max(dp[neighbor][0], dp[neighbor][1]);
            // 选当前节点时，子节点不能选
            dp[node][1] += dp[neighbor][0];
        }
    }
}

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4 1
1 2
2 3
3 4