#include<bits/stdc++.h>
using namespace std;
vector<int> ad[200001];
int dp[200001][2];
bool visited[200001], light[200001];
void dfs(int u)
{
visited[u] = 1;
for(int v : ad[u]) if(visited[v] == 0) dfs(v);
int sum = 0;
for(int v : ad[u]) if(visited[v] == 0) sum += dp[v][1];
dp[u][1] = max((int)light[u], sum - light[u]);
//calculate dp[u][0]
//Not activated case
int maxdif = 0, case1 = 0;
for(int v : ad[u]) if(visited[v] == 0){
maxdif = max(maxdif, max(dp[v][0], dp[v][1]));
case1 += dp[v][1];
}
if(ad[u].size()+(u==1) > 2) case1 -= light[u];
case1 = max(case1, maxdif);
//Activated case
int case2 = 0, sumcase = 0;
for(int v : ad[u]) if(visited[v] == 0){
case2 = max(case2, dp[v][1]);
sumcase += dp[v][1];
}
if(ad[u].size()+(u==1) > 2) sumcase -= light[u];
case2 += light[u];
case2 = max(case2, sumcase);
dp[u][0] = max(case1, case2);
visited[u] = 0;
//cout<<u<<" "<<dp[u][0]<<" "<<dp[u][1]<<'\n';
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin>>n;
for(int i = 0; i < n-1; i++){
int u, v;
cin>>u>>v;
ad[u].push_back(v);
ad[v].push_back(u);
}
for(int i = 1; i <= n; i++){
char x;
cin>>x;
light[i] = (x == '1');
}
dfs(1);
cout<<max(dp[1][0], dp[1][1]);
}
