#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int f[500005], d[500005], dd[500005], ff[500005], gg[500005];
vector<int> g[500005];
void dfs(int x, int p, int z, int c) {
if (f[x] > c) {
f[x] = c;
d[x] = 0;
}
if (f[x] == c) d[x] |= (1 << z);
for (int w : g[x]) {
if (w == p) continue;
dfs(w, x, z, c + 1);
}
}
int main() {
int n, k, c = 0;
cin >> n >> k;
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
if (abs(u - v) == 1) c++;
}
vector<int> v;
for (int i = 0; i < k; i++) {
int x;
cin >> x;
v.push_back(x);
}
sort(v.begin(), v.end());
if (c == n - 1) {
f[1] = 1;
gg[1] = 1;
ff[1] = v[0];
for (int i = 2; i <= k; i++) {
f[i] = 1e9;
if (v[i - 1] % 2 == v[i - 2] % 2) {
if (f[i] > f[i - 2] + 1) {
f[i] = f[i - 2] + 1;
ff[i] = (v[i - 1] + v[i - 2]) / 2;
gg[i] = 2;
}
}
if (f[i] > f[i - 1] + 1) {
f[i] = f[i - 1] + 1;
ff[i] = v[i - 1];
gg[i] = 1;
}
}
cout << f[k] << '\n';
int h = k;
while (h) {
cout << ff[h] << " ";
h = h - gg[h];
}
return 0;
}
if (k <= 15) {
for (int i = 1; i <= n; i++) {
f[i] = 1e9;
}
for (int i = 0; i < k; i++) {
dfs(v[i], -1, i, 0);
}
for (int i = 1; i <= n; i++) {
dd[d[i]] = i;
}
for (int i = 1; i < (1 << k); i++) f[i] = 1e9;
for (int i = 0; i < (1 << k); i++) {
if (f[i] == 1e9) continue;
for (int j = 1; j < (1 << k); j++) {
if (dd[j] == 0) continue;
int h = (i | j);
if (f[h] > f[i] + 1) {
f[h] = f[i] + 1;
ff[h] = dd[j];
gg[h] = i;
}
}
}
cout << f[(1 << k) - 1] << '\n';
int h = (1 << k) - 1;
while (h) {
cout << ff[h] << " ";
h = gg[h];
}
return 0;
}
}
