#include<bits/stdc++.h>
using namespace std;
using ll = long long;
//using LL = __int128
#define N 1000010
ll n, m, k, p[N], val[2][N], fa[N], sz[N];
vector<ll> g[N];
void add(int u, int v){
	g[u].push_back(v);
}
void dfs(int u, int f){
	for(auto v : g[u]){
		if(f == v)
			continue;
		dfs(v, u);
		sz[u] += sz[v];
	}
}
void dfs2(int u, int f){
	for(auto v : g[u]){
		if(f == v || !sz[v])
			continue;
		dfs2(v, u);
		val[1][u] += val[1][v] + 2;
	}
	val[0][u] = val[1][u];
	for(auto v : g[u]){
		if(f == v || !sz[v])
			continue;
		val[0][u] = min(val[0][u], val[1][u] - 1 - val[1][v] + val[0][v]);
	}
}
int main(){
	scanf("%lld%lld", &n, &m);
	for(int i = 1 ; i <= m ; i++){
		scanf("%lld", p + i);
		sz[p[i]]++;
	}
	for(int i = 1 ; i < n ; i++){
		int u, v;
		scanf("%d%d", &u, &v);
		add(u, v);
		add(v, u);
	}
	dfs(1, 1);
	dfs2(1, 1);
	printf("%lld", val[0][1]);
	return 0;
}