#include <bits/stdc++.h>
// #include <ext/rope>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
using namespace std;
// #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ll long long
#define ull unsigned long long
#define ld long double
#define pb push_back
#define bit(mask, i) ((mask >> i) & 1)
#define el '\n'
#define F first
#define S second
template <class X, class Y> bool maximize(X &x, const Y &y) { return (x < y ? x = y, 1 : 0); }
template <class X, class Y> bool minimize(X &x, const Y &y) { return (x > y ? x = y, 1 : 0); }
const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7;
const int MULTI = 0;
const ld eps = 1e-9;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0}; // R D L U
const int ddx[4] = {-1, 1, 1, -1}, ddy[4] = {1, 1, -1, -1}; // UR DR DL UL
const char cx[4] = {'R', 'D', 'L', 'U'};
const ll base = 31;
const int nMOD = 2;
const ll mods[] = {(ll)1e9 + 10777, (ll)1e9 + 19777, (ll)1e9 + 3, (ll)1e9 + 3777};
const int N = 2e5 + 5;
int n, dp[N], E[N], res;
vector<int> adj[N];
string s;
void dfs(int u, int p) {
int mx = 0, sum = 0;
for (int v: adj[u])
if (v != p) {
dfs(v, u);
maximize(mx, dp[v]);
sum += dp[v];
}
if (E[u])
maximize(res, max(mx + 1, sum - 1));
else
maximize(res, sum);
dp[u] = max(E[u], sum - E[u]);
}
void solve() {
cin >> n;
for (int i = 1, u, v; i < n; ++i) {
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
cin >> s;
for (int i = 1; i <= n; ++i)
E[i] = s[i - 1] - '0';
dfs(1, 0);
cout << res;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (!MULTI) solve();
else {
int test; cin >> test;
while (test--) solve();
}
return 0;
}
