<span>codeforces 700B Connecting Universities</span>

/* ***********************************************
Author        :devil
************************************************ */
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <stdlib.h>
using namespace std;
typedef long long LL;
const int inf=0x3f3f3f3f;
const int mod=1e9+7;
const int N=2e5+10;
int n,k,sum[N];
LL dp[N];
vector<int>eg[N];
void dfs(int u,int pre)
{
    dp[u]=0;
    for(int i=0;i<eg[u].size();i++)
    {
        int v=eg[u][i];
        if(v==pre) continue;
        dfs(v,u);
        sum[u]+=sum[v];
        dp[u]+=dp[v]+min(sum[v],k-sum[v]);
    }
}
int main()
{
    //freopen("in.txt","r",stdin);
    int x,y;
    scanf("%d%d",&n,&k);
    k<<=1;
    for(int i=0;i<k;i++)
    {
        scanf("%d",&x);
        sum[x]=1;
    }
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        eg[x].push_back(y);
        eg[y].push_back(x);
    }
    dfs(1,-1);
    printf("%I64d\n",dp[1]);
    return 0;
}