#include<bits/stdc++.h>
using namespace std;
int n;
vector<int> con[200005];
int dp[200005];
bool iss[200005];
int mxm=0;
void dfs(int nod, int par)
{
int sum=0,cntc=0;
for(auto adj:con[nod])
{
if(adj!=par)
{
dfs(adj,nod);
sum += dp[adj];
cntc++;
}
}
if(iss[nod])
{
dp[nod]=max(1, sum-1);
if(cntc==1)
mxm = max(mxm, sum+1);
}
else
{
dp[nod]=sum;
}
mxm = max(mxm, dp[nod]);
//cout<<nod<<" "<<dp[nod]<<"\n";
}
signed main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
int a,b;
cin>>n;
for(int i=1;i<n;i++)
{
cin>>a>>b;
con[a].push_back(b);
con[b].push_back(a);
}
int cnt1=0;
char ch;
for(int i=1;i<=n;i++)
{
cin>>ch;
if(ch=='1')
iss[i]=1;
else
iss[i]=0;
if(iss[i])
cnt1++;
}
dfs(1,0);
cout<<mxm;
return 0;
}
/**
dp[i] = scorul maxim pe care il putem obtine daca nu avem nicio statie stricata
*/
