#include <bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); i++)
#define R(i, j, k) for(int i = (j); i >= (k); i--)
#define all(x) x.begin(), x.end()
#define sz(a) ((int) a.size())
#define pb push_back
#define fst first
#define snd second
using namespace std;
typedef long long ll;
const int MAXN=2e5+5,INF=1e9;
vector<int>adj[MAXN];
int gen[MAXN];
int f(int u,int p){
int ret=0;
int diff_sum=0;
for(auto v:adj[u]){
if(v==p)continue;
diff_sum+=f(v,u);
}
ret=max(gen[u],max(0,diff_sum-gen[u]));
return ret;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;cin>>n;
L(i,0,n-2){
int a,b;cin>>a>>b;
a--;b--;
adj[a].pb(b);
adj[b].pb(a);
}
string s;cin>>s;
L(i,0,n-1)if(s[i]=='1')gen[i]=1;
int ans=0;
L(i,0,n-1){
ans=max(ans,f(i,i));
}
cout<<ans<<endl;
}
