// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
template<class T>
bool minimize(T &a, const T &b) {
if (a > b) return a = b, true;
return false;
}
template<class T>
bool maximize(T &a, const T &b) {
if (a < b) return a = b, true;
return false;
}
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"
const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int n, f[N], ans[N];
vector<int> G[N];
char c[N];
void dfs(int u, int par) {
for(int v : G[u]) if (v != par) {
dfs(v, u);
f[u] += f[v];
}
if (c[u] == '1') f[u] = max(f[u] - 1, 1);
}
void reroot(int u, int par) {
// re-calc f[u]
f[u] = 0;
for(int v : G[u]) if (v != par) {
f[u] += f[v];
}
if (c[u] == '1') f[u] = max(f[u] - 1, 1);
ans[u] = f[u];
for(int v : G[u]) if (v != par) // u : root -> choose one child and its descendants
maximize(ans[u], f[v] + (c[u] == '1'));
for(int v : G[u]) if (v != par) {
int old = f[u];
if (c[u] != '1' || f[u] > 1) // v contributes to f[u]
f[u] -= f[v];
reroot(v, u);
f[u] = old;
}
}
void init(void) {
cin >> n;
FOR(i, 2, n) {
int u, v;
cin >> u >> v;
G[u].pb(v);
G[v].pb(u);
}
FOR(i, 1, n) cin >> c[i];
}
void process(void) {
dfs(1, -1);
reroot(1, -1);
cout << *max_element(ans + 1, ans + n + 1);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) {
init();
process();
}
return 0;
}
