#include <bits/stdc++.h>
using namespace std;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n, k;
    cin >> n >> k;
    
    vector<bool> isBlack(n+1, false);
    for(int i = 0; i < k; i++){
        int b;
        cin >> b;
        isBlack[b] = true;
    }
    
    vector<vector<int>> adj(n+1);
    for(int i = 0; i < n-1; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    
    // Build set X: non-black vertices adjacent to at least one black vertex.
    vector<int> X;
    vector<bool> inX(n+1, false);
    for(int v = 1; v <= n; v++){
        if(isBlack[v]) continue;
        for(int nb : adj[v]){
            if(isBlack[nb]){
                if(!inX[v]){
                    inX[v] = true;
                    X.push_back(v);
                }
                break;
            }
        }
    }
    
    vector<bool> chosen(n+1, false);
    int countWhite = 0;
    
    // For each vertex in X, ensure that one of its neighbors is white.
    for(int u : X){
        bool found = false;
        for(int w : adj[u]){
            if(!isBlack[w] && chosen[w]){
                found = true;
                break;
            }
        }
        if(!found){
            int select = -1;
            for(int w : adj[u]){
                if(!isBlack[w]){
                    select = w;
                    break;
                }
            }
            // If no non-black neighbor found, select u itself.
            if(select == -1) select = u;
            if(!chosen[select]){
                chosen[select] = true;
                countWhite++;
            }
        }
    }
    
    cout << countWhite << "\n";
    return 0;
}