JAVA题解：

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] line = br.readLine().trim().split(" ");
        int N = Integer.parseInt(line[0]);  // 设备总量
        int M = Integer.parseInt(line[1]);  // 互斥设备数量
        int X = Integer.parseInt(line[2]);  // 指令数量
        
        // 读取互斥设备编号
        line = br.readLine().trim().split(" ");
        int[] mutexDevices = new int[M];
        for (int i = 0; i < M; i++) {
            mutexDevices[i] = Integer.parseInt(line[i]);
        }
        
        // 读取连接指令
        int[][] commands = new int[X][2];
        for (int i = 0; i < X; i++) {
            line = br.readLine().trim().split(" ");
            commands[i][0] = Integer.parseInt(line[0]);
            commands[i][1] = Integer.parseInt(line[1]);
        }
        
        // 计算并输出结果
        int result = countRejectedCommands(N, mutexDevices, commands);
        System.out.println(result);
    }
    
    public static int countRejectedCommands(int N, int[] mutexDevices, int[][] commands) {
        DisjointSetUnion dsu = new DisjointSetUnion(N);
        
        // 标记互斥设备
        for (int device : mutexDevices) {
            dsu.blocked[dsu.find(device)] = true;
        }
        
        int rejectedCount = 0;
        
        // 处理每条连接指令
        for (int[] command : commands) {
            int u = command[0];
            int v = command[1];
            
            int rootU = dsu.find(u);
            int rootV = dsu.find(v);
            
            // 如果两个设备的根都是互斥设备，则拒绝执行
            if (rootU != rootV && dsu.blocked[rootU] && dsu.blocked[rootV]) {
                rejectedCount++;
            } else {
                dsu.unite(u, v);
            }
        }
        
        return rejectedCount;
    }
    
    static class DisjointSetUnion {
        private int[] parent;
        private int[] size;
        boolean[] blocked;  // 标记互斥设备的根
        
        public DisjointSetUnion(int n) {
            parent = new int[n];
            size = new int[n];
            blocked = new boolean[n];
            
            for (int i = 0; i < n; i++) {
                parent[i] = i;
                size[i] = 1;
                blocked[i] = false;
            }
        }
        
        // 查找元素所属集合的根
        public int find(int x) {
            if (parent[x] != x) {
                parent[x] = find(parent[x]);  // 路径压缩
            }
            return parent[x];
        }
        
        // 合并两个集合
        public void unite(int a, int b) {
            int rootA = find(a);
            int rootB = find(b);
            
            if (rootA == rootB) {
                return;
            }
            
            // 按秩合并，将较小的树连接到较大的树上
            if (size[rootA] < size[rootB]) {
                int temp = rootA;
                rootA = rootB;
                rootB = temp;
            }
            
            parent[rootB] = rootA;
            size[rootA] += size[rootB];
            blocked[rootA] = blocked[rootA] || blocked[rootB];  // 更新互斥标记
        }
    }
}