#include <iostream>
#include <vector>
using namespace std;
int f[200005][2], a[200005];
vector<int> g[100005];
void dfs(int x, int p) {
if (p != -1 && g[x].size() == 1) {
f[x][0] = f[x][1] = a[x];
return;
}
int c = 0, d = g[x].size() - (p != -1);
if (d > 1) d = 1;
else d = 0;
for (int w : g[x]) {
if (w == p) continue;
dfs(w, x);
c += f[w][1];
f[x][0] = max(f[x][0], f[w][0]);
f[x][0] = max(f[x][0], f[w][1] + a[x]);
}
f[x][1] = max(a[x], c - a[x]);
f[x][0] = max(f[x][0], c - a[x] * d);
//cout << x << " " << f[x][1] << " " << f[x][0] << '\n';
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n;
cin >> n;
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
string s;
cin >> s;
s = " " + s;
for (int i = 1; i <= n; i++) a[i] = (s[i] == '1');
dfs(1, -1);
cout << max(f[1][0], f[1][1]);
}
