#include<cstdio>
#include<vector>
#define ll long long
int read(){
	int num=0;
	char ch;ch=getchar();
	while(ch<48||ch>57)ch=getchar();
	while(ch>47&&ch<58){
		num=(num<<1)+(num<<3)+(ch^48);
		ch=getchar();
	}return num;
}
void swap(int &x,int &y){x^=y;y^=x;x^=y;}
const int N=2e5+5;
const int M=N<<1;
int n,m;
int em,e[N<<1],nx[N<<1],ls[N];
void insert(int x,int y){
	e[++em]=y;
	nx[em]=ls[x];
	ls[x]=em;
}
int fir[N],fa[N];
ll dep[N];
int dfn[M],sum;
void dg1(int x,int father){
	fa[x]=father;
	dep[x]=dep[father]+1;
	dfn[++sum]=x,fir[x]=sum;
	for(int i=ls[x];i;i=nx[i]){
		if(e[i]==father)continue;
		dg1(e[i],x);dfn[++sum]=x;
	}
}
int f[M][25];
int lo[M],w[25];
int Q(int l,int r){
	if(l>r)swap(l,r);
	int x=lo[r-l+1];
	if(dep[f[l][x]]<dep[f[r-w[x]+1][x]])return f[l][x];
	return f[r-w[x]+1][x];
}
struct node{
	int x,y;
	ll val;
};
std::vector<node>E[N];
int rt[N];
ll ans;
struct Node{
	int lson,rson;
	int L,R;
	ll sum;
	ll s;
};
Node v[N<<7];int cnt;
void change(int &x,int l,int r,int p,int val){
	if(!x)x=++cnt;
	if(l==r){
		v[x].s+=val;
		if(v[x].s){
			v[x].sum=dep[dfn[p]];
			v[x].L=v[x].R=p;
		}else v[x].sum=0;
		return;
	}int mid=(l+r)>>1;
	if(mid>=p)change(v[x].lson,l,mid,p,val);
	else change(v[x].rson,mid+1,r,p,val);
	v[x].s=0;
	if(!v[x].lson||!v[v[x].lson].s){
		v[x].L=v[v[x].rson].L;
		v[x].R=v[v[x].rson].R;
		v[x].s=v[v[x].rson].s;
		v[x].sum=v[v[x].rson].sum;
		return;
	}
	if(!v[x].rson||!v[v[x].rson].s){
		v[x].L=v[v[x].lson].L;
		v[x].R=v[v[x].lson].R;
		v[x].s=v[v[x].lson].s;
		v[x].sum=v[v[x].lson].sum;
		return;
	}
	v[x].L=v[v[x].lson].L,v[x].R=v[v[x].rson].R;
	v[x].s=v[v[x].lson].s+v[v[x].rson].s;
	v[x].sum=v[v[x].lson].sum+v[v[x].rson].sum;
	v[x].sum-=2*dep[Q(v[v[x].lson].R,v[v[x].rson].L)];
}
int merge(int x,int y,int l,int r){
	if(!x||!y)return x+y;
	if(l==r){
		v[x].s+=v[y].s;
		v[x].sum+=v[y].sum;
		if(v[x].s){
			v[x].sum=dep[dfn[l]];
			v[x].L=v[x].R=l;
		}else v[x].sum=0;
		return x;
	}
	int mid=(l+r)>>1;
	v[x].lson=merge(v[x].lson,v[y].lson,l,mid);
	v[x].rson=merge(v[x].rson,v[y].rson,mid+1,r);
	if(!v[x].lson||!v[v[x].lson].s){
		v[x].L=v[v[x].rson].L;
		v[x].R=v[v[x].rson].R;
		v[x].s=v[v[x].rson].s;
		v[x].sum=v[v[x].rson].sum;
		return x;
	}
	if(!v[x].rson||!v[v[x].rson].s){
		v[x].L=v[v[x].lson].L;
		v[x].R=v[v[x].lson].R;
		v[x].s=v[v[x].lson].s;
		v[x].sum=v[v[x].lson].sum;
		return x;
	}
	v[x].L=v[v[x].lson].L,v[x].R=v[v[x].rson].R;
	v[x].s=v[v[x].lson].s+v[v[x].rson].s;
	v[x].sum=v[v[x].lson].sum+v[v[x].rson].sum;
	v[x].sum-=dep[Q(v[v[x].lson].R,v[v[x].rson].L)];
	return x;
}
void dg2(int x,int father){
	for(int i=ls[x];i;i=nx[i]){
		if(e[i]==father)continue;
		dg2(e[i],x);
		rt[x]=merge(rt[x],rt[e[i]],1,sum);
	}
	for(int i=0;i<E[x].size();i++){
		change(rt[x],1,sum,fir[E[x][i].x],E[x][i].val);
		change(rt[x],1,sum,fir[E[x][i].y],E[x][i].val);
	}
	if(v[rt[x]].s){
		ans+=v[rt[x]].sum-dep[Q(v[rt[x]].L,v[rt[x]].R)];
	}
}
int main(){
	n=read(),m=read();
	for(int i=1,p,q;i<n;i++){
		p=read(),q=read();
		insert(p,q);
		insert(q,p);
	}dg1(1,0);lo[0]=-1;
	for(int i=1;i<=sum;i++){
		f[i][0]=dfn[i];
		lo[i]=lo[i>>1]+1;
	}
	for(int i=0;i<23;i++)w[i]=1<<i;
	for(int i=1;i<20;i++)for(int j=1;j+w[i]-1<=sum;j++)	{
		if(dep[f[j][i-1]]<dep[f[j+w[i-1]][i-1]])f[j][i]=f[j][i-1];
		else f[j][i]=f[j+w[i-1]][i-1];
	}
	for(int i=1,p,q,lca;i<=m;i++){
		p=read(),q=read();
		lca=Q(fir[p],fir[q]);
		E[p].push_back(node{p,q,1});
		E[q].push_back(node{p,q,1});
		E[lca].push_back(node{p,q,-1});
		E[fa[lca]].push_back(node{p,q,-1});
	}
	dg2(1,0);
	printf("%lld",ans/4);
	return 0;
}