//####################
//PowerPlant
//####################
#include<bits/stdc++.h>
using namespace std;
const int maxiN = 2*1e5;
bool isPowerPlant[maxiN];
vector<int> links[maxiN];
int dp[2][maxiN];
int ans = 0;
int solve(bool ataken,int node,int dad=-1){
if(dp[ataken][node]!=-1)return dp[ataken][node];
if(ataken==0){
int sum = 0;
int bestsub = 0;
for(int v:links[node])if(v!=dad){
int x = solve(0,v,node);
bestsub = max(bestsub,x);
sum += x;
ans = max(ans, isPowerPlant[node] + solve(1,v,node));
}
if(bestsub<1)bestsub=isPowerPlant[node];
if(bestsub>1)bestsub-=isPowerPlant[node];
ans = max(ans,max(sum-isPowerPlant[node],bestsub));
return dp[ataken][node] = max(sum-isPowerPlant[node],bestsub);
}else{
int sum = 0;
int bestsub = 0;
for(int v:links[node])if(v!=dad){
int x = solve(0,v,node);
bestsub = max(bestsub,x);
sum += x;
}
ans = max(ans, max(sum-isPowerPlant[node],bestsub));
return dp[ataken][node] = max(sum-isPowerPlant[node],bestsub);
}
}
signed main(){
ios::sync_with_stdio(false);
int n;cin>>n;
for(int i = 1;i<n;i++){
int a,b;cin>>a>>b;
a--;
b--;
links[a].push_back(b);
links[b].push_back(a);
}
fill(dp[0],dp[0]+n,-1);
fill(dp[1],dp[1]+n,-1);
string binary;cin>>binary;
for(int i= 0;i<n;i++)isPowerPlant[i] = (binary[i]=='1');
solve(0,0);
cout<<ans<<endl;
return 0;
};
