#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
int n;
str s;
vector <vector<int>> v;
ll ans = 0;
int snd;
ll dfs(int nd, int ss){
ll r = '0'-s[nd];
if(ss == -1 && v[nd].size() == 1) r = 1;
for(int x: v[nd]) if(x != ss) r+=dfs(x, nd);
//cout << nd << " " << r << " " << s[nd] - '0' << " de\n";
return max(r, (ll)s[nd] - '0');
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
v = vector<vector<int>> (n+1);
for(int i = 1; i < n; i++){
int a, b; cin >> a >> b;
v[a].pb(b);
v[b].pb(a);
}
cin >> s;
s = "x"+s;
for(int i = 1; i <= n; i++) if(s[i] == '1') ans = max(ans, dfs(i, -1));
//cout << dfs(2, -1) << "\n";
cout << ans << "\n";
}
