#include <bits/stdc++.h>
using namespace std;
const int NMAX=2e5;
int n, dp[NMAX+5], mx=0;
vector <int> vec[NMAX+5];
string input;
void dfs (int nod, int tatal=0)
{
int s=0, mxc=0;
for (auto adj : vec[nod])
{
if (adj==tatal)
continue;
dfs (adj, nod);
if (dp[adj]>mxc)
{
mxc=dp[adj];
}
dp[nod]+=dp[adj];
}
dp[nod]-=(input[nod]-'0');
dp[nod]=max (dp[nod], input[nod]-'0');
mx=max (mx, max (mxc+input[nod]-'0', dp[nod]));
}
int main ()
{
cin >> n;
for (int i=1;i<n;i++)
{
int x, y;
cin >> x >> y;
vec[x].push_back (y);
vec[y].push_back (x);
}
cin >> input;
input='#'+input;
dfs (1);
cout << mx;
return 0;
}
