#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define ll long long
#define ld long double
#define pb push_back
#define endl '\n'
#define ff first
#define mp make_pair
#define ss second
#define ull unsigned long long
#define YES cout << "YES" << endl;
#define NO cout << "NO" << endl;
#define ulongmax 18446744073709551615
#define pll pair<ll,ll>
using namespace std;

ll maxn = -1e18;
ll minn = 1e18;
ll mod = 1e9 + 7;
const int maxx = 2e5 + 5;
const int base = 311;
vector<ll> node[maxx];
pair<ll,ll> a[maxx];
ll dp[maxx][20], dep[maxx];
map<ll,map<ll,ll>> mem;
stack<ll> s;
ll pa[maxx];
bool flag;
void dfs(ll u, ll par){
        for (int i = 1; i < 20; i++){
                dp[u][i] = dp[dp[u][i - 1]][i - 1];
        }
        for (auto j :node[u]){
                if (j != par){
                        dep[j] = dep[u] + 1;
                        dp[j][0] = u;
                        pa[j] = u;
                        dfs(j, u);
                }
        }
}
ll lca(ll u, ll v){
        if (dep[u] > dep[v]) swap(u, v);
        ll d = dep[v] - dep[u];
        for (int i = 0; i < 20; i++){
                if (d >> i & 1){
                        v = dp[v][i];
                }
        }
        if (u == v) return u;
        for (int i = 19; i >= 0; i--){
                if (dp[u][i] != dp[v][i]){
                        u = dp[u][i];
                        v = dp[v][i];
                }
        }
        return dp[u][0];
}
ll dt(ll x, ll y){
        return dep[x] + dep[y] - 2 * dep[lca(x, y)];
}
bool cmp(pair<ll,ll> x, pair<ll,ll> y){
        if (lca(x.ff, x.ss) == lca(y.ff, y.ss)) {
                if (lca(x.ff, x.ss) == x.ff || lca(x.ff, x.ss) == x.ss) return true;
                if (lca(y.ff, y.ss) == y.ff || lca(y.ff, y.ss) == y.ss) return false;
                return dt(x.ff, x.ss) < dt(y.ff, y.ss);
        }
        return dep[lca(x.ff, x.ss)] > dep[lca(y.ff, y.ss)];
}
int main(){
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
        //freopen("HACK.TXT","r",stdin);
        //freopen(".INP","r",stdin);
        //freopen(".OUT","w",stdout);
        //freopen("HACK.TXT","w",stdout);
        ll n, m;
        cin >> n >> m;
        for (int i = 1; i < n; i++){
                ll x, y;
                cin >> x >> y;
                node[x].pb(y);
                node[y].pb(x);
        }
        dfs(1, 0);
        for (int i = 1; i <= m; i++){
                cin >> a[i].ff >> a[i].ss;
        }
        sort(a + 1, a + m + 1, cmp);
        ll ans = 0;
        for (int i = 1; i <= m; i++) {
                flag = true;
                if (dep[a[i].ff] > dep[a[i].ss])swap(a[i].ff, a[i].ss);
                ll x = a[i].ff, y = a[i].ss, z = lca(a[i].ff, a[i].ss);
                vector<ll> b, c;
                b.clear(), c.clear();
                while (true){
                        b.pb(x);
                        if (x == z) break;
                        x = pa[x];
                }
                while (true){
                        if (y == z) break;
                        c.pb(y);
                        y = pa[y];
                }
                reverse(all(c));
                for (auto j : c) b.pb(j);
                //for (auto j : b) cout << j << " ";
                //cout << endl;
                for (int j = 1; j < b.size(); j++){
                        if (mem[b[j]][b[j - 1]] == 1) {
                                flag = false;
                                break;
                        }
                }
                if (flag == true){
                        ans++;
                        for (int j = 1; j < b.size(); j++){
                                mem[b[j]][b[j - 1]] = 1;
                                mem[b[j - 1]][b[j]] = 1;
                        }
                }
        }
        cout << ans;
}