#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int32_t main () {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int N;
cin >> N;
vector<int> g[N];
for (int i = 1;i < N;i ++) {
int u, v;
cin >> u >> v;
-- u; -- v;
g[u].push_back(v);
g[v].push_back(u);
}
string S;
cin >> S;
int mx = 0;
for (int i = 0;i < N;i ++) {
vector<int> dp(N, 0);
function<void(int, int)> dfs = [&](int si, int pi) -> void {
int tmp = 0;
for (auto ti : g[si]) if (ti != pi) {
dfs(ti, si);
tmp += dp[ti];
}
if (g[i].size() == 1 && si == i) {
dp[si] = max(S[si] - '0', tmp + (S[si] - '0'));
} else {
dp[si] = max(S[si] - '0', tmp - (S[si] - '0'));
}
};
dfs(i, i);
mx = max(mx, dp[i]);
}
cout << mx << "\n";
}
