#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll maxn = 2e5 + 5;
vector<ll> adj[maxn];
string s;
ll ans = 1;
ll dp[maxn];
void dfs(ll src, ll parent)
{
ll maxt = -1;
for (auto sex: adj[src])
{
if (sex != parent)
{
dfs(sex, src);
dp[src] += dp[sex];
maxt = max(maxt, dp[sex]);
}
}
ll gay = s[src - 1] - '0';
dp[src] = max(gay, dp[src] - gay);
ans = max({ans, maxt + gay, dp[src]});
}
int main()
{
ll n;
cin >> n;
ll u, v;
for (ll i = 1; i <= n - 1; ++i)
{
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
cin >> s;
dfs(1, 0);
cout << ans;
}
