#include<iostream>
#include<cstdio>
#include<vector>
#define N 100000
using namespace std;
const int inf=(int)(1e9);
int read()
{
	char c=0;
	int sum=0;
	while (c<'0'||c>'9') c=getchar();
	while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
	return sum;
}
int n,m,ans,fa[N+1],depth[N+1],dis[N+1],DP[N+1];
vector<int>E[N+1];
vector<int>ES[N+1];
bool used[N+1],vis[N+1],vst[N+1];
void add(int x,int y)
{
	E[x].push_back(y),E[y].push_back(x);
	return;
}
void add2(int x,int y)
{
	ES[x].push_back(y),ES[y].push_back(x);
	return;
}
void dfs(int x)
{
	used[x]=1;
	for (int i=0;i<E[x].size();++i)
		if (!used[E[x][i]])
			fa[E[x][i]]=x,dfs(E[x][i]);
	return;
}
void dfs2(int x)
{
	int rt=0,minn=inf,minn2=inf;
	used[x]=1,vst[x]=vis[x];
	for (int i=0;i<ES[x].size();++i)
		if (fa[fa[x]]==ES[x][i])
			dis[x]=min(dis[x],dis[ES[x][i]]+1);
	if (vis[x]) DP[x]=min(DP[x],depth[x]+dis[x]+1);
	for (int i=0;i<E[x].size();++i)
		if (!used[E[x][i]])
		{
			fa[E[x][i]]=x,depth[E[x][i]]=depth[x]+1,dis[E[x][i]]=dis[x]+1,dfs2(E[x][i]),vst[x]|=vst[E[x][i]];
			if (vst[E[x][i]])
			{
				if (depth[x]+dis[E[x][i]]<minn) minn2=minn,minn=depth[x]+dis[E[x][i]],rt=i;
				else if (depth[x]+dis[E[x][i]]<minn2) minn2=depth[x]+dis[E[x][i]];
			}
		}
	for (int i=0;i<E[x].size();++i)
		if (fa[E[x][i]]==x)
		{
			if (rt==i) DP[E[x][i]]=min(DP[E[x][i]],minn2);
			else DP[E[x][i]]=min(DP[E[x][i]],minn);
		}
	return;
}
void dfs3(int x)
{
	for (int i=0;i<E[x].size();++i)
		if (fa[E[x][i]]==x)
			DP[E[x][i]]=min(DP[E[x][i]],DP[x]),dfs3(E[x][i]);
	return;
}
int main()
{
	int x,y;
	n=read(),m=read();
	for (int i=1;i<=n-1;++i) x=read(),y=read(),add(x,y);
	dfs(1);
	for (int i=1;i<=m;++i)
	{
		x=read(),y=read(),add2(x,y);
		if (fa[x]!=y&&fa[y]!=x&&fa[x]!=fa[y]&&fa[fa[x]]!=y&&x!=fa[fa[y]]) vis[x]=vis[y]=1;
    }
	for (int i=1;i<=n;++i)
	{
		for (int j=1;j<=n;++j) used[j]=fa[j]=0,DP[j]=inf;
		depth[i]=1,dis[i]=0,dfs2(i),dfs3(i);
		for (int j=1;j<=n;++j)
			if (i!=j&&depth[j]>=DP[j])
				ans++;
	}
	printf("%d\n",ans);
	return 0;
}