//#pragma optimization_level 3
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include<bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordset;
*/
#define fr first
#define sc second
#define vec vector
#define pb push_back
#define pii pair<int, int>
#define forn(x,y) for(int x = 1 ; x <= (int)y ; ++x)
#define all(x) (x).begin(),(x).end()
#define fast cin.tie(0);cout.tie(0);cin.sync_with_stdio(0);cout.sync_with_stdio(0);
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef pair<ll,ll> pll;
typedef complex<int> point;
const int nmax = 200005;
const ll linf = 1e18;
const ll mod = 998244353;
const int inf = 1e9+10;
const int sq = 5000;
int n;
char asd[nmax];
int viz[nmax];
vec < int > g[nmax];
int dp[nmax];
int rez;
void cm(int nod , int parent){
int rs = (asd[nod] == '1');
int rs2 = -(asd[nod] == '1');
for(int i : g[nod]){
if(i == parent)continue;
cm(i,nod);
rs2 += dp[i];
rs = max(rs , dp[i] + (asd[nod] == '1'));
}
dp[nod] = rs2;
if(asd[nod] == '1')dp[nod] = max(dp[nod],1);
rez = max(rez , rs2);
rez = max(rez , rs);
}
int main(){
cin >> n;
for(int i = 1; i < n; i++){
int a, b;
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
}
for(int i = 1; i <= n; i++){
cin >> asd[i];
}
cm(1,0);
cout << rez << '\n';
}
