#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for(int i=a; i<b; i++)
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
#define fo(i, n) rep(i, 0, n)
#define F first
#define S second
#define MP make_pair
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;

const int NMAX = 112345;
const int LOGMAX = 25;

int n,k;

struct Nd *sta[NMAX];
struct Nd{
	vector<Nd *> e;
	int h;
	bool is_here;
	bool is_upper;

	vector<int> at_here;
	vector<int> at_upper;

	int opt_solved;
	int opt_unsolved;

	Nd * up[LOGMAX];
	void go(Nd * from=NULL, int hh=0)
	{
		h =hh;
		up[0]=from;
		fo(i,LOGMAX-1) up[i+1] = up[i]?up[i]->up[i]:0;
		for(Nd * x : e) if(x!=from) x->go(this, h+1);
	}
	void go2()
	{
		sta[h]=this;
		for(int x : at_here) sta[x]->is_here=true;
		for(int x : at_upper) sta[x]->is_upper=true;
		for(Nd * x : e) if(x!=up[0]) x->go2();
	}
	void go3()
	{
		for(Nd * x : e) if(x!=up[0]) x->go3();
		int with = 1;
		int without = is_here;
		for(Nd * x : e) if(x!=up[0]) with += x->opt_unsolved;
		for(Nd * x : e) if(x!=up[0]) without += x->opt_solved;

		opt_solved = min(with, is_upper?without+1:without);
		opt_unsolved = min(with, without);
	}
}nds[NMAX];

Nd * nca(Nd *a, Nd *b)
{
	if(b->h > a->h) return nca(b,a);

	for(int i=LOGMAX;i-->0;)
		if(a->up[i] && a->up[i]->h >= b->h)
			a = a->up[i];

	for(int i=LOGMAX;i-->0;)
		if(a->up[i] != b->up[i])
			a=a->up[i], b=b->up[i];

	if(a==b) return a;
	return a->up[0];
}

void add(Nd *a, Nd * b)
{
	if(b->h > a->h) return add(b,a);

	Nd *c = nca(a,b);

	int l = a->h + b->h - 2*c->h;

	if(l%2)
	{
		a->at_upper.push_back(a->h-l/2);
	}
	else
	{
		a->at_here.push_back(a->h-l/2);
	}
}


int main() {
	scanf("%d%d", &n,&k);

	fo(i,n-1)
	{
		int a,b;
		scanf("%d%d",&a, &b);
		nds[a].e.push_back(nds+b);
		nds[b].e.push_back(nds+a);
	}

	nds->go();


	fo(i,k)
	{
		int a,b;
		scanf("%d%d",&a, &b);
		add(nds+a, nds+b);
	}

	nds->go2();
	nds->go3();

	//fo(i,n) printf("%d: %d %d : %d %d\n", i, nds[i].is_here, nds[i].is_upper, nds[i].opt_solved, nds[i].opt_unsolved);

	printf("%d\n", nds->opt_solved);

}


/*
7 5
0 1
0 2
2 5
1 4
4 6
1 3
1 6
1 3
3 2
1 5
2 5
0: 0 0 : 3 3
1: 0 1 : 2 2
2: 0 1 : 1 1
3: 0 1 : 1 0
4: 1 0 : 1 1
5: 0 1 : 1 0
6: 0 0 : 0 0
3

*/