// Hydro submission #6746da599592d6097b868d46@1732696666034
#include<bits/stdc++.h>
#define int long long
using namespace std;
int n;
int a[100010],b[100010],p[100010],fa[100010];
vector<int> g[100010];
struct Node{
    int u,a,b;
    friend bool operator<(Node x,Node y)
	{
        if((x.a<x.b)!=(y.a<y.b))return y.a<y.b;
        return x.a<x.b?x.a>y.a:x.b<y.b;
    }
};
priority_queue<Node> pq;
void dfs(int u,int fat)
{
    fa[u]=fat;
    for(int v:g[u])if(v!=fat)dfs(v,u);
}
int find(int x)
{
    if(p[x]!=x)p[x]=find(p[x]);
    return p[x];
}
signed main()
{
    int i;
    cin>>n;
    for(i=2;i<=n;i++)cin>>a[i]>>b[i];
    for(i=1;i<=n;i++)p[i]=i;
    for(i=1;i<n;i++){
        int a,b;
        cin>>a>>b;
        g[a].push_back(b),g[b].push_back(a);
    }
    dfs(1,0);
    for(i=2;i<=n;i++)pq.push({i,a[i],b[i]});
    while(pq.size()){
        Node x=pq.top();
		pq.pop();
        if(x.u==1||a[x.u]!=x.a||b[x.u]!=x.b||find(x.u)!=x.u)continue;
        int u=x.u,v=find(fa[u]),c=max(a[v],a[u]+a[v]-b[v]),d=c-a[u]+b[u]-a[v]+b[v];
        p[u]=v,a[v]=c,b[v]=d,pq.push({v,a[v],b[v]});
    }
    cout<<a[1];
}