#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3,unroll-loops")
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
const int inf = 1e17,N = 3e5+1,MOD = 1e9+7,BL = 1000;
vi edges[N],dp(N);
string c;
int dfs(int node,int p) {
int sm = 0;
for (auto it : edges[node]) {
if (it == p) continue;
int d = dfs(it,node);
sm += d;
}
dp[node] = max(0ll,sm-(c[node-1] == '1'));
if (c[node-1] == '1') dp[node] = max(dp[node],1ll);
return dp[node];
}
void solve() {
int n;
cin >> n;
for (int i=1;i<n;i++) {
int a,b;
cin >> a >> b;
edges[a].push_back(b);
edges[b].push_back(a);
}
cin >> c;
if (n <= 2) {
cout << count(all(c),'1') << '\n';
return;
}
int ans = 0;
for (int i=1;i<=n;i++) {
if (c[i-1] == '0') continue;
dfs(i,i);
ans = max(ans,dp[i]);
}
cout << ans << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#ifdef Dodi
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
