#include <iostream>
#include <vector>
using namespace std;
vector<int> g[200005];
int a[200005], f[200005][5];
void dfs(int x, int p) {
int c = 0, d = 0, ma = 0, ma2 = 0;
for (int w : g[x]) {
if (w == p) continue;
dfs(w, x);
c += f[w][1];
ma = max(ma, max(f[w][0], f[w][1]));
ma2 = max(ma2, f[w][1]);
}
d = c;
f[x][1] = max(a[x], c - a[x]);
if (x == 1 && g[x].size() > 1) c -= a[x];
else if (g[x].size() > 2) c -= a[x];
c = max(c, ma);
if (x == 1 && g[x].size() > 1) d -= a[x];
else if (g[x].size() > 2) d -= a[x];
ma2 += a[x];
ma2 = max(ma2, d);
f[x][0] = max(ma2, c);
}
int main() {
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++) {
if (s[i] == '1') a[i] = 1;
}
dfs(1, -1);
cout << max(f[1][0], f[1][1]);
}
