#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

#define ll long long
#define ll128 __uint128_t
#define ld long double
#define vll vector <ll>
#define vvll vector <vll>
#define pll pair <ll, ll>

#define rep(i, a, b) for(ll i = a; i < b; i++)
#define per(i, a, b) for(ll i = a - 1; i >= b; --i)

#define endl "\n"
#define pb push_back
#define pf push_front

#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()

#define sorta(v) sort(all(v))
#define sortd(v) sort(rall(v))
#define vld vector<ld>

#define debug if (1)
#define log(val) debug {cout << "\n" << #val << ": " << val << "\n";}

#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

#define mod (ll)(1e9 + 7)

using namespace std;
using namespace __gnu_cxx;
using namespace __gnu_pbds;

ostream & operator << (ostream & out, vll & a) {
    for(auto i : a) out << i << " ";
    return out;
}

istream & operator >> (istream & in, vll & a) {
    for(auto &i : a) in >> i;
    return in;
}

const ll N = 3 * 1e5 + 10;

vll g[N];
ll tin[N], tout[N];
const ll logn = 20;
ll up[N][logn];
ll timer = 1;

ll h[N];

void dfs(ll v = 0, ll p = 0, ll curh = 1) {
    tin[v] = timer++;
    h[v] = curh;
    up[v][0] = p;
    rep(i, 1, logn + 1) {
        up[v][i] = up[up[v][i - 1]][i - 1];
    }
    for(auto i : g[v]) {
        if(i != p) {
            dfs(i, v, curh + 1);
        }
    }
    tout[v] = timer++;
}

bool parent(ll a, ll b) {
    return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}

ll lca(ll a, ll b) {
    if(parent(a, b)) return a;
    if(parent(b, a)) return b;
    for(int i = logn; i >= 0; i--) {
        if(!parent(up[a][i], b)) a = up[a][i];
    }
    return up[a][0];
}

int main() {
    // freopen("input.txt","r", stdin);
    // freopen("output.txt","w", stdout);

    ll n, k;
    cin >> n >> k;

    vll a(n + 1);
    rep(i, 1, n + 1) {
        cin >> a[i];
    }
    for (auto &i : a) i--;
    rep(i, 0, n - 1) {
        ll v1, v2;
        cin >> v1 >> v2;
        g[v1 - 1].pb(v2 - 1);
        g[v2 - 1].pb(v1 - 1);
    }
    dfs(0);
    vvll dp(n + 1, vll(k + 1, 1e18));

    if (n == 1) {
        return cout << h[a[1]], 0;
    }

    dp[0][0] = 0;

    rep (i, 0, n) {
        // cout << i << endl;
        rep(j, 0, k) {
            dp[i + 1][j] = min(dp[i + 1][j], dp[i][j]);
            dp[i + 1][j + 1] = min(dp[i + 1][j + 1], dp[i][j] + h[a[i + 1]]);
            if (i + 2 <= n) {
                dp[i + 2][j + 1] = min(dp[i + 2][j + 1], dp[i][j] + h[lca(a[i + 1], a[i + 2])]);
            }
        }
    }
    /*
    rep(i, 0, n + 1) {
        rep(j, 0, k + 1) {
            cout << dp[i][j] << " ";
        }
        cout << endl;
    }
    */
    cout << dp[n][k] << endl;

    return 0;
}