Notes

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define loop(a,n) for(ll i = a; i < n; i++)
#define loop2(a,n) for(ll j = a; j < n; j++)
#define trace(x) for(auto it:x)
using namespace std;

const ll MAX = 1e5+5;
const ll MOD = 1e9 + 7;
const ll inf = 1e18;
const ll level = 18;
vector<ll>adj[MAX];

ll par[MAX] = {}, sum[MAX] = {};
ll vis[MAX] = {};
ll rnk[MAX]= {};
ll depth[MAX] = {};
ll parent[MAX][level];
void dfs(int u, int v){

par[u] = v;

depth[u] = depth[v] + 1;
parent[u][0] = v;
vis[u] = 1;
trace(adj[u]){

if(!vis[it]){

dfs(it, u);
}
}

}

int LCA(int u, int v)
{
if(depth[u] < depth[v])
return LCA(v, u);
int diff = depth[u] - depth[v];
for (int i = 0; i < 15; ++i)
{
if((diff>>i) & 1)
u = parent[u][i];
}
if(u != v)
{
for (int i = 14; i >= 0; --i)
{
if(parent[u][i] != parent[v][i])
{
u = parent[u][i];
v = parent[v][i];
}
}
u = parent[u][0];
}
return u;
}
void solve(int v){

trace(adj[v]){

if(it - par[v])
{

solve(it);
sum[v] += sum[it];
}
}

}

void bfs(ll v){

queue<ll>q;

q.push(v);
rnk[v] = 1;

while(!q.empty()){

ll u = q.front();
vis[u] = 1;
q.pop();

// cout<<u<<endl;
trace(adj[u]){

if(it - par[u])
{
rnk[it] = rnk[u] + 1;
q.push(it);
}
}
}
}
int main() {

memset(&parent,0,sizeof(parent));

ll n, m;
cin>>n>>m;

loop(0, n - 1){

ll u, v;
cin>>u>>v;

adj[u].pb(v);
adj[v].pb(u);

}

dfs(1, 0);
//memset(&vis, 0, sizeof vis);

for(int i = 0; i < 15; ++i){
for (int j = 1; j <= n; ++j)
{
if(parent[j][i] != 0)
parent[j][i+1]=parent[parent[j][i]][i];
}
}
bfs(1);

//loop(1, 2 + n)cout<<rnk[i]<<" ";
//cout<<endl;
loop(0, m){

ll x, y;
cin>>x>>y;

ll lca = LCA(x,y);
if(rnk[x] > rnk[y])swap(x,y);

// cout<<x<<" "<<y<<endl;

if(lca != x && lca != y){
sum[x]++;
sum[y]++;
sum[lca]--;
sum[par[lca]]--;
}else{
sum[y]++;
sum[par[x]]--;
}
}

solve(1);

//loop(1, 1 + n)cout<<sum[i]<<" ";
ll ans = 0;
//cout<<endl;
loop(1, 1 + n)ans = max(ans, sum[i]);

cout<<ans;
return 0;
}