#include <bits/stdc++.h>
#define Y8o "main"
#define maxn (int) 2e5 + 5
#define ll long long
#define pii pair<int, int>
#define gb(i, j) ((i >> j) & 1)
#define all(x) x.begin(), x.end()
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define fi(i, a, b) for(int i = a; i <= b; i ++)
#define fid(i, a, b) for(int i = a; i >= b; i --)
//#define f first
//#define s second
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
return uniform_int_distribution<ll> (l, r) (rng);
}
void iof() {
ios_base::sync_with_stdio(0);
cin.tie(NULL), cout.tie(NULL);
if(fopen(Y8o".inp", "r"))
{
freopen(Y8o".inp", "r", stdin);
// freopen(Y8o".out", "w", stdout);
}
}
void ctime() {
cerr << "\n" << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}
int n;
string S;
vector<int> o[maxn];
int dp[maxn], ans; /// dp[u] dam bao ko co chuoi 2 tu con len to tien
void dfs(int u = 1, int p = 0) {
int sum = 0, mx = 0, ok = (S[u] == '1');
for(int v : o[u]) if(v != p) {
dfs(v, u);
sum += dp[v], mx = max(mx, dp[v]);
}
ans = max({ ans, sum - ok, mx + ok });
dp[u] = max({ ok, sum - ok });
}
void solve() {
cin >> n ;
fi(i, 1, n - 1) {
int u, v; cin >> u >> v;
o[u].push_back(v), o[v].push_back(u);
}
cin >> S, S = ' ' + S;
dfs();
cout << ans;
}
int main() {
iof();
int nTest = 1;
// cin >> nTest;
while(nTest --) {
solve();
}
ctime();
return 0;
}
