#include <bits/stdc++.h>
using namespace std;
int N, sol = 1;
string S;
bitset <200001> B;
int DP[200001];
vector <int> VG[200001];
void DFS(int node, int parent = 0)
{
int dp = 0, cnt = 0;
for(int x : VG[node])
{
if(x == parent) continue;
DFS(x, node);
dp += DP[x];
cnt += bool(DP[x]);
DP[node] = max(DP[x], DP[node]);
}
DP[node] = max(dp, DP[node]);
if(cnt > 1) sol = max(DP[node] - B[node], sol);
else sol = max(DP[node] + B[node], sol);
DP[node] = max(DP[node] - B[node], (int)B[node]);
// cout << node << ": " << B[node] << ' ' << DP[node] << ' ' << dp << ' ' << cnt << '\n';
return;
}
int main()
{
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin >> N;
int u, v;
for(int i = 1; i < N; i++)
{
cin >> u >> v;
VG[u].push_back(v);
VG[v].push_back(u);
}
cin >> S;
for(int i = 1; i <= N; i++) B[i] = S[i - 1] == '1';
for(int i = 1; i <= N; i++) DFS(i);
cout << sol << '\n';
return 0;
}
