#include<bits/stdc++.h>
#define ll long long
#define N 100005
using namespace std;
inline char nc(){
	static char buf[1000000],*p=buf,*q=buf;
	return p==q&&(q=(p=buf)+fread(buf,1,1000000,stdin),p==q)?EOF:*p++;
}
inline ll read(){
	ll res = 0,w = 1;
	char c = nc();
	while(c<'0'||c>'9')w=(c=='-'?-1:w),c=nc();
	while(c<='9'&&c>='0')res=res*10+c-'0',c=nc();
	return res*w;
}
char obuf[1<<21],*p3=obuf; 
inline void pc(char c){ 
	p3-obuf<=(1<<20)?(*p3++=c):(fwrite(obuf,p3-obuf,1,stdout),p3=obuf,*p3++=c); 
} 
inline void write(ll x){ 
	if(x<0) pc('-'),x=-x; 
	if(x>9) write(x/10); 
	pc(x%10+'0'); 
}
vector<ll> extra[N];
ll n,m,i,x,y,la[N],ne[N<<1],to[N<<1],et,vis[N],st[N][21],dep[N],key[N],keyboard[N],ans,col[N],tim,si[N],st_cut[N][21],st_extra[N][21],depp[N],next_root,fath[N],dis0[N],dis1[N],type[N],DIS[N],FATH[N],instack[N];
vector<ll> v1,v2;
struct BIT{
	ll tr[N];
	inline void add(ll k,ll x){while(k<=n) tr[k]+=x,k+=k&(-k);}
	inline ll query(ll k){
		ll num = 0;
		while(k) num+=tr[k],k-=k&(-k);
		return num;
	}
	inline void clear(ll k){while(k<=n) tr[k]=0,k+=k&(-k);}
}tr1,tr2;
inline void merge(ll x,ll y){
	et++,ne[et]=la[x],la[x]=et,to[et]=y;
	et++,ne[et]=la[y],la[y]=et,to[et]=x;
}
inline void dfs(ll x,ll fa){
	FATH[x] = fa;
	for(ll i=1;i<=17;i++) st[x][i]=st[st[x][i-1]][i-1];
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa) continue;
		dep[to[i]] = dep[x]+1,st[to[i]][0] = x;
		dfs(to[i],x);
	}
}
inline void dfs2(ll x,ll fa){
	keyboard[x] = vis[x];
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa) continue;
		dfs2(to[i],x);
		keyboard[x] += keyboard[to[i]];
	}
}
inline ll dis11(ll x,ll y){
	ll ans = dep[x]+dep[y];
	if(dep[x]>dep[y]) swap(x,y);
	for(ll i=17;i>=0;i--) if(dep[st[y][i]]>=dep[x]) y=st[y][i];
	if(x==y) return ans-2*dep[x];
	for(ll i=17;i>=0;i--) if(st[x][i]!=st[y][i]) x=st[x][i],y=st[y][i];
	return ans-2*dep[st[x][0]];
}
inline void find_root(ll x,ll fa,ll &pos,ll &num,ll alls){
	ll now = 0;
	si[x] = 1;
	for(ll i=la[x];i;i=ne[i]){
		if(col[to[i]]!=col[x]||to[i]==fa) continue;
		find_root(to[i],x,pos,num,alls);
		si[x] += si[to[i]],now = max(now,si[to[i]]);
	}
	now = max(now,alls-si[x]);
	if(now<num) num=now,pos=x;
}
inline void init(ll x,ll fa,ll root){
	if(fa==-1) key[x]=keyboard[1];
	else{
		key[x]=keyboard[1];
		for(ll i=la[x];i;i=ne[i]){
			if(to[i]==fa){
				if(to[i]==FATH[x]) key[x]=keyboard[x];
				else key[x]-=keyboard[to[i]];
			}
		}
	}
	si[x] = (col[x]==col[root]),fath[x] = fa,dis0[x] = 0x3f3f3f3f,dis1[x] = 0x3f3f3f3f;
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa) continue;
		depp[to[i]] = depp[x] + 1; 
		init(to[i],x,root);
		si[x] += si[to[i]];
	}
}
inline void dfs_col(ll x,ll fa){
	for(ll i=la[x];i;i=ne[i]){
		if(col[to[i]]!=col[x]||to[i]==fa) continue;
		dfs_col(to[i],x);
	}
	col[x]=tim;
}
inline void dfs_insert_b(ll x,ll fa,ll delta){
	cerr<<"** tr1-add "<<depp[x]<<" "<<delta<<endl;
	tr1.add(depp[x],delta);
	for(ll i=la[x];i;i=ne[i]) if(col[to[i]]==col[x]&&to[i]!=fa) dfs_insert_b(to[i],x,delta);
}
inline ll foundd(ll x,ll deppp){
	ll ans = 0;
	for(ll i=17;i>=0;i--) if(st_extra[x][i]&&depp[st_extra[x][i]]>deppp) x=st_extra[x][i],ans+=(1ll<<i);
	return ans+(depp[x]>deppp);
}
inline bool found2(ll x,ll y){
	for(ll i=la[x];i;i=ne[i]) if(to[i]==y) return 1;
	return 0;
}
inline void dfs_find_a(ll x,ll fa,ll root){
	instack[x]=1;
	if(depp[x]==1) st_extra[x][0]=fa;
	else{
		st_extra[x][0]=fa;
		for(ll i=0;i<extra[x].size();i++) if(depp[extra[x][i]]==depp[x]-2) st_extra[x][0]=extra[x][i];
	}
	for(ll i=1;i<=17;i++) st_cut[x][i]=st_cut[st_cut[x][i-1]][i-1];
	for(ll i=1;i<=17;i++) st_extra[x][i]=st_extra[st_extra[x][i-1]][i-1];
	if(key[x]){
		//Pos 作为 B 
		ans+=tr1.query(n)+1;
		cerr<<"A1 is "<<x<<" ans is "<<(tr1.query(n)+1)<<endl;
	}
	else{
		vector<ll> v(0);
		ll pos = x,step = -1,delta = -1;
		for(ll i=17;i>=0;i--) if(st_cut[pos][i]&&!key[st_cut[pos][i]]) pos=st_cut[pos][i];
		for(ll i=0;i<extra[pos].size();i++) if(depp[extra[pos][i]]==depp[pos]&&key[extra[pos][i]]) v.push_back(extra[pos][i]);
		if(v.size()) step=foundd(x,depp[pos])+1,delta=depp[v[0]];
		else step=foundd(x,depp[st_cut[pos][0]]),delta=depp[st_cut[pos][0]];
		pos=st_cut[pos][0];
		//Pos 作为 B 
		cerr<<"pos is B when "<<step<<" "<<delta<<" "<<pos<<" "<<v.size()<<endl;
		ll temp = 0;
		if(step-delta<0) ans++,temp=1;
		ans+=tr1.query(n)-tr1.query(max(0ll,step-delta));
		cerr<<"A2 is "<<x<<" ans is "<<tr1.query(n)-tr1.query(max(0ll,step-delta))+temp<<endl;
		if(pos==root&&v.size()==1&&col[v[0]]==col[x]){
			next_root = v[0];
			cerr<<"v1 v2 pushback "<<step<<" "<<foundd(x,depp[pos])<<" "<<v1.size()<<" "<<v2.size()<<endl;
			v1.push_back(step),v2.push_back(foundd(x,depp[pos]));
			cerr<<"v1 v2 size is "<<v1.size()<<" "<<v2.size()<<endl;
		}
	}
	for(ll i=la[x];i;i=ne[i]){
		if(col[to[i]]!=col[x]||to[i]==fa) continue;
		st_cut[to[i]][0] = x;
		dfs_find_a(to[i],x,root);
	}
	for(ll i=0;i<=17;i++) st_cut[x][i]=0,st_extra[x][i]=0;
	instack[x]=0;
}
inline void dfss(ll x,ll fa,ll type){
	if(type==0) ans -= tr2.query(depp[x]),cerr<<"v1 v2 erase "<<tr2.query(depp[x])<<endl;
	else ans += tr2.query(depp[x]-1),cerr<<"v1 v2 insert "<<tr2.query(depp[x]-1)<<endl;
	for(ll i=la[x];i;i=ne[i]) if(col[to[i]]==col[x]&&to[i]!=fa) dfss(to[i],x,type);
}
inline void dfs_find_b(ll x,ll fa,ll root){
	instack[x] = 1;
	for(ll i=1;i<=17;i++) st_cut[x][i]=st_cut[st_cut[x][i-1]][i-1];
	if(fa!=root) dis0[x] = 0x3f3f3f3f,dis1[x] = 0x3f3f3f3f;
	dis0[x] = min(dis0[x],dis0[fa]+1),dis1[x] = min(dis1[x],dis1[fa]+1);
	for(ll i=0;i<extra[x].size();i++){
		if(depp[extra[x][i]]==depp[x]-2){
			dis0[x] = min(dis0[x],dis0[extra[x][i]]+1);
			dis1[x] = min(dis1[x],dis1[extra[x][i]]+1);
		}
	}
	ll pos = x;
	for(ll i=17;i>=0;i--) if(st_cut[pos][i]&&key[root]-key[st_cut[pos][i]]) pos=st_cut[pos][i];
	cerr<<"DFN init b's grand...father is "<<pos<<" "<<st_cut[pos][0]<<" "<<key[root]<<" "<<key[pos]<<endl;
	if(st_cut[pos][0]&&(key[root]-key[pos])) pos=st_cut[pos][0];
	ll cntt = key[root];
	for(ll i=la[pos];i;i=ne[i]) if(instack[to[i]]) cntt -= key[to[i]];
	cerr<<"dfn find b "<<x<<" "<<pos<<" "<<"cntt is "<<cntt<<endl;
	if(cntt){
		ll temp = 0;
		for(ll i=0;i<extra[fath[pos]].size();i++) if(depp[extra[fath[pos]][i]]==depp[pos]+1&&!instack[extra[fath[pos]][i]]&&found2(extra[fath[pos]][i],pos)) temp=1;
		if(fath[pos]!=root){
			ll step = -1,dis00 = -1,dis11 = -1;
			if(temp==0) step=depp[x]-depp[pos],dis00 = dis0[pos],dis11 = dis1[pos];
			else step=depp[x]-depp[pos]+1,dis00 = dis0[fath[pos]]+1,dis11 = dis1[fath[pos]]+1;
			cerr<<"Situation 1 "<<pos<<" "<<step<<" "<<dis00<<" "<<dis11<<endl;
			//Pos 作为 A 点 
			if(step-1-dis00>=0) ans++,cerr<<"AA1 is "<<root<<" ans is "<<1<<endl;
			ans+=tr1.query(max(step-1-dis00,0ll));
			ans+=tr2.query(max(step-1-dis11,0ll));
			cerr<<"B-P turn's A1 "<<tr1.query(max(step-1-dis00,0ll))<<" "<<tr2.query(max(step-1-dis11,0ll))<<endl;
		}
		else{
			ll step = -1,dis00 = -1,dis11 = -1;
			if(temp==0) step=depp[x]-depp[pos],dis00 = dis0[pos],dis11 = dis1[pos];
			else step=depp[x]-depp[pos]+1,dis00 = 1,dis11 = 1;
			cerr<<"Situation 2 "<<pos<<" "<<step<<" "<<dis00<<" "<<dis11<<" "<<temp<<endl;
			//Pos 作为 A 点 
			if(step-1-dis00>=0) ans++,cerr<<"AA2 is "<<root<<" ans is "<<1<<endl;
			ans+=tr1.query(max(step-1-dis00,0ll));
			ans+=tr2.query(max(step-1-dis11,0ll));
			cerr<<"B-P turn's A2 "<<tr1.query(max(step-1-dis00,0ll))<<" "<<tr2.query(max(step-1-dis11,0ll))<<endl;
		}
	}
	cerr<<"AFTER THIS "<<x<<" WE HAVE TO DO ANS IS "<<ans<<endl;	
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa||col[to[i]]!=col[x]) continue;
		st_cut[to[i]][0] = x;
		dfs_find_b(to[i],x,root);
	}
	for(ll i=0;i<=17;i++) st_cut[x][i]=0;
	instack[x] = 0;
}
inline bool found(ll x,ll y){
	for(ll i=0;i<extra[x].size();i++) if(extra[x][i]==y) return 1;
	return 0;
}
inline void dfs_insert_a(ll x,ll fa){
	if(type[x]==0) tr1.add(DIS[x],1);
	if(type[x]==1) tr2.add(DIS[x],1),cerr<<"type is 1 point has "<<x<<" "<<DIS[x]<<endl;
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa||col[to[i]]!=col[x]) continue;
		if(found(to[i],fa)) DIS[to[i]]=DIS[fa]+1,type[to[i]]=type[fa];
		else DIS[to[i]]=DIS[x]+1,type[to[i]]=type[x];
		dfs_insert_a(to[i],x);
	}
}
inline void dfs_erase_a(ll x,ll fa){
	if(type[x]==0) tr1.add(DIS[x],-1);
	if(type[x]==1) tr2.add(DIS[x],-1);
	for(ll i=la[x];i;i=ne[i]){
		if(to[i]==fa||col[to[i]]!=col[x]) continue;
		dfs_erase_a(to[i],x);
	}
}
inline void dfs_alls(ll x,ll fa,ll &alls){
	alls++;
	for(ll i=la[x];i;i=ne[i]) if(col[to[i]]==col[x]&&to[i]!=fa) dfs_alls(to[i],x,alls);
}
inline void solve(ll x){
	memset(tr1.tr,0,sizeof(tr1.tr));
	ll pos = -1,num = LLONG_MAX,cnt_key_son = 0,alls = 0;
	dfs_alls(x,-1,alls);
	if(alls==1) return ;	
	find_root(x,-1,pos,num,alls);
	depp[pos] = 0,init(pos,-1,pos);
	for(ll i=la[pos];i;i=ne[i]){
		ll keys = 0;
		if(FATH[pos]==to[i]) keys=keyboard[1]-keyboard[pos];
		else keys=keyboard[to[i]];
		if(keys) cnt_key_son++;
	}
	for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) dfs_insert_b(to[i],pos,1);
	cerr<<"! "<<pos<<endl;
	if(!(cnt_key_son==1&&!vis[pos])){
		cerr<<"type is A-P\n";
		//在 A-P 上 
		ans += (alls-1); //Pos 作为 A 点 
		cerr<<"A is "<<pos<<" ans is "<<(alls-1)<<endl;
		for(ll i=la[pos];i;i=ne[i]){
			if(col[to[i]]==col[pos]){
				next_root = -1;
				st_cut[to[i]][0] = pos;
				dfs_insert_b(to[i],pos,-1);
				dfs_find_a(to[i],pos,pos);
				if(next_root!=-1){
					cerr<<"V1V2 SIZE IS "<<v1.size()<<" "<<v2.size()<<endl;
					for(ll j=0;j<v1.size();j++) tr2.add(v1[j],1);
					dfss(next_root,pos,0);
					for(ll j=0;j<v1.size();j++) tr2.clear(v1[j]);
					for(ll j=0;j<v2.size();j++) tr2.add(v2[j],1);
					dfss(next_root,pos,1);
					for(ll j=0;j<v2.size();j++) tr2.clear(v2[j]);
					v1.clear(),v2.clear();
				}
				dfs_insert_b(to[i],pos,1);
			}
		}
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) dfs_insert_b(to[i],pos,-1);
	}
	else{
		cerr<<"type is B-P\n";
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]&&key[to[i]]) dfs_insert_b(to[i],pos,-1);
		//在 B-P（不包含） 上 
		for(ll i=la[pos];i;i=ne[i]){
			if(col[to[i]]==col[pos]){
				st_cut[to[i]][0] = pos;
				if(!key[to[i]]) dfs_insert_b(to[i],pos,-1);
				dfs_find_a(to[i],pos,pos);
				v1.clear(),v2.clear();
				if(!key[to[i]]) dfs_insert_b(to[i],pos,1);
			}
		}
		ll root = -1;
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]&&!key[to[i]]) dfs_insert_b(to[i],pos,-1);
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) if(key[to[i]]) root=to[i];
		ll num = 0;
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) if(!key[to[i]]) ans+=si[to[i]],num+=si[to[i]];
		cerr<<"A-root is "<<pos<<" ans is "<<num<<" "<<ans<<endl;
		type[pos]=0,DIS[pos]=0;
		for(ll i=la[pos];i;i=ne[i]){
			if(col[to[i]]==col[pos]){
				if(!key[to[i]]){
					if(found(to[i],root)) DIS[to[i]]=1,type[to[i]]=1,cerr<<"HAS EXTRA EDGE "<<to[i]<<" "<<root<<endl;
					else DIS[to[i]]=1,type[to[i]]=0;
					dfs_insert_a(to[i],pos);
				}
			} 
		}
		cerr<<"BEFORE B SOLVED ANS IS "<<ans<<endl;
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) if(key[to[i]]) dis0[to[i]]=1,dis1[to[i]]=0,dfs_find_b(to[i],pos,pos);
		for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) if(!key[to[i]]) dfs_erase_a(to[i],pos);
	}
//	for(ll i=1;i<=n;i++) assert(tr1.tr[i]==0);
	cerr<<"root is "<<pos<<" ans is "<<ans<<endl;
	for(ll i=la[pos];i;i=ne[i]) if(col[to[i]]==col[pos]) tim++,dfs_col(to[i],pos),solve(to[i]);
}
int main(){
	ll has = 0;
	n=read(),m=read();
	for(i=1;i<n;i++) x=read(),y=read(),merge(x,y);
	dep[1]=1,dfs(1,-1);
	for(i=1;i<=m;i++){
		x=read(),y=read();
		ll temp = dis11(x,y);
		if(temp==1) continue;
		if(temp==2) extra[x].push_back(y),extra[y].push_back(x);
		if(temp>2) vis[x]=1,vis[y]=1,has=1; 
	}
	if(!has){
		write(0);
		return fwrite(obuf,p3-obuf,1,stdout),0;
	}
	dfs2(1,-1);
	for(i=1;i<=n;i++) cerr<<vis[i]<<" ";
	cerr<<endl;
	for(i=1;i<=n;i++) cerr<<keyboard[i]<<" ";
	cerr<<endl;
	solve(1);
	write(ans);
	return fwrite(obuf,p3-obuf,1,stdout),0;
}