#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, a, b, f[200000], h[200000], res;
string s;
vector<int> g[200000];
bool valid[200000];
inline void DFS1(int node, int par)
{
h[node] = 0;
for (auto &i : g[node])
{
if (i != par)
{
DFS1(i, node);
h[node] += f[i];
}
}
f[node] = max(h[node] - valid[node], (int)valid[node]);
}
inline void DFS2(int node, int par, int cur)
{
res = max(res, f[node] + cur);
for (auto & i : g[node])
{
if (i != par)
{
DFS2(i, node, max((int)valid[node], h[node] - f[i] + cur - valid[node]));
}
}
}
int main()
{
setup();
cin >> n;
for (int i = 0; i < n - 1; ++i)
{
cin >> a >> b;
g[a - 1].push_back(b - 1);
g[b - 1].push_back(a - 1);
}
cin >> s;
for (int i = 0; i < n; ++i)
{
valid[i] = (s[i] == '1');
}
DFS1(0, 0);
DFS2(0, 0, 0);
cout << res;
return 0;
}
