#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int long long
typedef pair<int, int> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define lowbit(x) x&-x;
const int maxn = 2e5 + 5;
const int INF = 1e18;
vector<int> adj[maxn];
int st[maxn], dp[maxn];
int ans = 0;
void dfs(int pos, int prev){
int ttl = 0, ad = 0, mx = 0;
for(auto x : adj[pos]){
if(x == prev) continue;
dfs(x, pos);
if(dp[x] == 0) continue;
mx = max(mx, dp[x]);
ttl += dp[x];
ad++;
}
ans = max(ans, mx + st[pos]);
dp[pos] = max(ttl - st[pos], st[pos]);
ans = max(ans, dp[pos]);
}
signed main(void){
fastio;
int n;
cin>>n;
for(int i = 0; i < n - 1; i++){
int a, b;
cin>>a>>b;
a--, b--;
adj[a].pb(b);
adj[b].pb(a);
}
string s;
cin>>s;
for(int i = 0; i < n; i++) st[i] = (s[i] == '1');
dfs(0, -1);
cout<<ans<<"\n";
}
