// Hydro submission #6746cb169592d6097b8668cf@1732692759037
#include<bits/stdc++.h>
#define int long long
using namespace std;
int n;
vector<int> e[100005];
int a[100005],b[100005];
namespace union_find
{
    int fa[100005];
    void init(int n){for(int i=1;i<=n;i++)fa[i]=i;}
    int root(int x){return (fa[x]==x?x:fa[x]=root(fa[x]));}
    void merge(int u,int v){u=root(u),v=root(v),fa[u]=v;}
};
int fa[100005];
void dfs(int pos,int fa)
{
    ::fa[pos]=fa;
    for(int x:e[pos])
    {
        if(x==fa)
            continue;
        dfs(x,pos);
    }
}
bool f[100005];
struct node
{
    int id,a,b;
    bool operator < (const node x) const
    {
        bool f1=(b>=0);
        bool f2=(x.b>=0);
        if(!f1&&f2)
            return 1;
        if(f1&&!f2)
            return 0;
        if(f1&&f2)
            return a>x.a;
        else
            return b+a<x.b+x.a;
    }
};
void test()
{
    cin>>n;
    for(int i=2;i<=n;i++)
        cin>>a[i]>>b[i],f[i]=0,b[i]-=a[i];
    for(int i=1;i<n;i++)
    {
        int u,v;
        cin>>u>>v;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    union_find::init(n);
    dfs(1,0);
    priority_queue<node> q;
    for(int i=2;i<=n;i++)
        q.push({i,a[i],b[i]});
    while(!q.empty())
    {
        node x=q.top();
        q.pop();
        if(a[x.id]!=x.a||b[x.id]!=x.b||f[x.id])
            continue;
        // cout<<x.id<<" "<<x.a<<" "<<x.b<<" "<<union_find::root(fa[x.id])<<"\n";
        int rt=union_find::root(fa[x.id]);
        f[x.id]=1;
        a[rt]=max(a[rt],a[x.id]-b[rt]);
        b[rt]=b[rt]+b[x.id];
        if(rt!=1)
            q.push({rt,a[rt],b[rt]});
        union_find::merge(x.id,rt);
    }
    cout<<a[1]<<"\n";
}
signed main()
{
    freopen("tree.in","r",stdin);
    freopen("tree.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    test();
}
/*
5
1 3
3 2
1 2
9 5
2 1
3 1
4 2
5 2
*/