#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 2e5 + 5;
int n, a[maxn];
int f[maxn], sum[maxn];
string s;
vector<int> g[maxn];
int res;
void dfs(int u, int prev) {
for(auto v:g[u]) {
if(v == prev) continue;
dfs(v, u);
f[u] = max(f[u], f[u] + f[v]);
res = max(res, f[v] + a[u]);
}
f[u] = max(f[u] - a[u], a[u]);
res = max(res, f[u]);
debug(u, a[u], f[u]);
}
void solve() {
cin >> n;
for(int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
cin >> s;
for(int i = 1; i <= n; ++i) {
a[i] = (s[i - 1] - '0');
}
dfs(1, 0);
cout << res;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
