/*#pragma GCC optimize("O3")
#pragma GCC optimization("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")*/
#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pair<ll, ll>>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
const ll INF = 1e18+7;
const int lg = 20;
const ll MOD = 1e9+7;
//const ll MOD2 = 998244353;
//const ll MOD3 = 1e6+3;
mt19937 rng(1488);
ll randll(ll l, ll r) {
return uniform_int_distribution<ll>(l, r)(rng);
}
vvll g;
str s;
ll maxl = 0;
ll dfs(ll v, ll p = -1) {
vll a;
ll res = 0;
for (int i : g[v]) {
if (i == p) continue;
ll c = dfs(i, v);
if (c > 0) {
a.pb(c);
res += c;
}
}
sort(a);
if (s[v-1] == '1') {
ll res1 = res;
res = max(res-1, (ll)1);
if (a.size() <= 1) res1 ++;
else if (a.size() == 2 && a[0] == 1) {
}
else res1 --;
maxl = max(maxl, res1);
}
maxl = max(maxl, res);
return res;
}
int main() {
speed;
ll n;
cin >> n;
g.resize(n+7);
for (int i = 0; i < n-1; i ++) {
ll a, b;
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
}
cin >> s;
dfs(1);
cout << maxl << endl;
}
