#include<bits/stdc++.h>
#define taskname "C"
using namespace std;
const int lim = 2e5 + 5;
template<class T>void maximize(T& a, T b){
if(a < b){
a = b;
}
}
int n;
namespace sub1{
void solve(){
vector<vector<int>>g(n);
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
g[--u].emplace_back(--v);
g[v].emplace_back(u);
}
string s;
cin >> s;
vector<int>h(n), parent(n);
auto dfs = [&] (auto&& self, int s) -> void{
for(int& d : g[s]){
if(d != parent[s]){
h[d] = h[parent[d] = s] + 1;
self(self, d);
}
}
};
dfs(dfs, h[0] = parent[0] = 0);
int ans = 0;
for(int mask = (1 << n) - 1; mask > 0; mask--){
vector<int>vertex;
bool flag = true;
for(int i = 0; i < n; i++){
if(1 << i & mask){
if(s[i] == '0'){
flag = false;
break;
}
vertex.emplace_back(i);
}
}
if(flag){
vector<bool>color(n, true);
int sum = 0;
for(int& u : vertex){
for(int& v : vertex){
vector<int>path;
int U = u, V = v;
while(U != V){
if(h[U] < h[V]){
swap(U, V);
}
path.emplace_back(U = parent[U]);
}
for(int& i : path){
if(i != u && i != v && s[i] == '1' && color[i]){
color[i] = false;
sum--;
}
}
}
}
for(int& i : vertex){
if(color[i]){
sum++;
}
}
maximize(ans, sum);
}
}
cout << ans;
}
}
namespace sub2{
void solve(){
vector<vector<int>>g(n);
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
g[--u].emplace_back(--v);
g[v].emplace_back(u);
}
string s;
cin >> s;
for(char& c : s){
c -= 48;
}
vector<int>dp(n);
auto dfs = [&] (auto&& self, int u, int p) -> void{
dp[u] = 0;
for(int& v : g[u]){
if(v != p){
self(self, v, u);
dp[u] += max(int(s[v]), dp[v] - s[v]);
}
}
};
int ans = -1;
for(int i = 0; i < n; i++){
if(s[i] == 1){
dfs(dfs, i, -1);
for(int& j : g[i]){
maximize(ans, max(int(s[j]), dp[j] - s[j]));
}
}
}
cout << ans + 1;
}
}
namespace sub3{
const int lim = 2e5 + 5;
vector<int>g[lim];
string s;
int ans = -1, dp[lim];
void dfs_1(int u, int p = -1){
dp[u] = 0;
for(int& v : g[u]){
if(v != p){
dfs_1(v, u);
dp[u] += max(int(s[v]), dp[v] - s[v]);
}
}
}
void dfs_2(int u, int p = -1){
if(s[u] == 1){
for(int& v : g[u]){
maximize(ans, max(int(s[v]), dp[v] - s[v]));
}
}
for(int& v : g[u]){
if(v != p){
dp[u] -= max(int(s[v]), dp[v] - s[v]);
if(p != -1){
dp[u] += max(int(s[p]), dp[p] - s[p]);
}
dfs_2(v, u);
dp[u] += max(int(s[v]), dp[v] - s[v]);
if(p != -1){
dp[u] -= max(int(s[p]), dp[p] - s[p]);
}
}
}
}
void solve(){
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
g[--u].emplace_back(--v);
g[v].emplace_back(u);
}
cin >> s;
for(char& c : s){
c -= 48;
}
dfs_1(0);
dfs_2(0);
cout << ans + 1;
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if(fopen(taskname".inp", "r")){
freopen(taskname".inp", "r", stdin);
}
cin >> n;
if(n <= 16){
sub1::solve();
}
else if(n <= 2000){
sub2::solve();
}
else{
sub3::solve();
}
}
