#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
#define pb push_back

using namespace std;

vector<int> a;
vector< vector<int> > g;
int ans = 0;

void dfs(int cur, int pre, int state) {
    // cout << cur << ' ' << pre << ' ' << state << endl;
    int c0 = 0, c1 = 0;
    for(int ver : g[cur]) if(ver != pre) {
            if(a[ver]) ++ c1;
            else ++ c0;
        }

    state |= a[cur];
    // cout << c0 << ' ' << c1 << ' ' << state << endl << endl;
    if(!state) {
        ++ ans;
        for(int ver : g[cur]) if(ver != pre) dfs(ver, cur, 0);
    } else {
        if(c0 == 0) return ;
        ++ ans;
        for(int ver : g[cur]) if(ver != pre) dfs(ver, cur, c0 == 1);
    }
}

int main() {
    if(fopen("yl.in", "r")) {
        freopen("yl.in", "r", stdin);
        freopen("yl.out", "w", stdout);
    }
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m, u, v;
    cin >> n >> m;
    a.resize(n + 1);
    g.resize(n + 1);
    rep(i,1,n - 1) {
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    rep(i,1,m) {
        cin >> u;
        a[u] = 1;
    }
    dfs(1, 0, 0);
    cout << ans << endl;
    return 0;
}