// #pragma GCC optimize("O3,Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define MP make_pair
#define pb push_back
#define REP(i,n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const double EPS = 0.00001;
const int INF = 1e9+500;
const int N = 3e5+5;
const int ALPH = 26;
const int LGN = 25;
constexpr int MOD = 1e9+7;
int n,m,q;
vector<vector<int> > adj;
vector<int> isPow;
vector<int> dp;
int ans = 0;
void dfs(int node, int par) {
int sum = 0;
for(auto c : adj[node]) {
if(c == par) continue;
dfs(c, node);
sum += dp[c];
}
dp[node] = max(isPow[node], sum - isPow[node]);
if(isPow[node]) {
for(auto c : adj[node]) {
ans = max(ans, dp[c] + 1);
}
}
}
inline void solve() {
cin>>n;
adj.assign(n + 1, vector<int>());
isPow.assign(n + 1, 0);
dp.assign(n + 1, 0);
REP(i, n - 1) {
int a,b;
cin >> a >> b;
adj[a].pb(b);
adj[b].pb(a);
}
for(int i = 1; i <= n; i++) {
char x;
cin >> x;
if(x == '1') isPow[i] = 1;
}
dfs(1, 0);
ans = max(ans, dp[1]);
cout << ans << "\n";
}
signed main() {
//fastio();
int test = 1;
//cin>>test;
while(test--) {
solve();
}
}
