#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define BIT(mask, x) ((mask >> (x)) & 1)
#define FOR(i, a, b) for (int i = a, _b = b; i <= _b; ++i)
#define FORD(i, a, b) for (int i = a, _b = b; i >= _b; --i)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
// -------------------------------------- CON CUA BO HCN --------------------------------------
const int maxn = 2e5 + 3;
int n, dp[maxn], Up[maxn], res;
vector<int> g[maxn];
bitset<maxn> has;
// --------------------------------------------------------------------------------------------
void dfs_down(int u, int p)
{
for (int v : g[u])
{
if (v == p) continue;
dfs_down(v, u);
dp[u] += dp[v];
}
if (has[u])
{
if (dp[u] == 1) res = max(res, 2);
--dp[u];
}
dp[u] = max(dp[u], (int)has[u]);
res = max(res, dp[u]);
}
void dfs_up(int u, int p)
{
int sum = 0;
for (int v : g[u])
{
if (v == p) continue;
sum += dp[v];
}
for (int v : g[u])
{
if (v == p) continue;
Up[v] = Up[u] + sum - dp[v];
res = max(res, dp[v] + Up[v]);
if (has[v]) --Up[v];
dfs_up(v, u);
}
}
void solve()
{
cin >> n;
FOR(i, 2, n)
{
int u, v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
FOR(i, 1, n)
{
char op; cin >> op;
has[i] = op - '0';
}
dfs_down(1, -1);
Up[1] = has[1];
dfs_up(1, -1);
cout << res;
}
signed main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define TASK "TEST"
if (fopen(TASK".INP", "r"))
{
freopen(TASK".INP", "r", stdin);
freopen(TASK".OUT", "w", stdout);
}
solve();
return 0;
}
/* NOTES:
*/
