#include <bits/stdc++.h>
using namespace std;
int n, m;
const int N = 1e5 + 10, M = N * 2;
int h[N], e[M], ne[M], idx;
int fa[N][17], depth[N];
int d[N];
int q[N];
int ans;

void add(int a, int b)
{
    e[idx] = b, ne[idx] = h[a], h[a] = idx ++;
}

void bfs()
{
    memset(depth, 0x3f, sizeof depth);
    int hh = 0, tt = 0;
    depth[0] = 0, depth[1] = 1;
    q[0] = 1;

    while (hh <= tt)
    {
        int t = q[hh ++];
        for (int i = h[t]; ~i; i = ne[i])
        {
            int j = e[i];
            if (depth[j] > depth[t] + 1)
            {
                depth[j] =  depth[t] + 1;
                q[++ tt] = j;
                fa[j][0] = t;
                for (int k = 1; k <= 16; k ++)
                    fa[j][k] = fa[fa[j][k - 1]][k - 1];
            }
        }
    }
}

int lca(int a,int b)
{
    if (depth[a] < depth[b]) swap(a, b);
    for (int i = 16; i >= 0; i --)
        if (depth[fa[a][i]] >= depth[b])
            a = fa[a][i];
    if (a == b) return a;
    for (int i = 16; i >= 0; i --)
        if (fa[a][i] != fa[b][i])
        {
            a = fa[a][i];
            b = fa[b][i];
        }
    return fa[a][0];
}

int dfs(int u, int fa)
{
    int res = d[u];
    for (int i = h[u]; ~i; i = ne[i])
    {
        int j = e[i];
        if (j != fa)
        {
            int s = dfs(j, u);
            if (s == 0) ans += m;
            else if (s == 1) ans ++;
            res += s;
        }
    }
    return res;
}

int main(void)
{
    cin >> n >> m;
    memset(h, -1, sizeof h);
    for (int i = 0; i < n - 1; i ++)
    {
        int a, b;
        cin >> a >> b;
        add(a, b), add(b, a);
    }
    bfs();
    for (int i = 0; i < m; i ++)
    {
        int a, b;
        cin >> a >> b;
        int p = lca(a, b);
        d[a] ++, d[b] ++, d[p] -= 2;
    }
    dfs(1, -1);
    printf("%d", ans);
    return 0;
}