#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in array<int, 2>
#define pb push_back
#define pob pop_back
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int MX = 2e5+5;
const int INF = 1e17;
vector<int> adj[MX];
bool S[MX];
int dp[2][2][MX];
void dfs(int u, int p)
{
int V = 0; int W = 0; int UU = 0;
int rr = 0;
for(int v: adj[u])
{
if(v==p)
continue;
rr++;
dfs(v, u);
V = max(V, max(dp[0][0][v], dp[0][1][v]));
UU = max(UU, max(dp[1][0][v], dp[1][1][v]));
W+=max(dp[1][0][v], dp[1][1][v]);
}
if(rr == 0)
{
dp[0][0][u] = 0;
dp[0][1][u] = S[u];
dp[1][0][u] = 0;
dp[1][1][u] = S[u];
return;
}
//Case: Nothing selected at u, or its parent.
//We ignore the root, and compute cost without it. Yet, we enable the foundation.
dp[0][0][u] = max(0ll, max(V, W-S[u]));
dp[0][1][u] = max(0ll, max(UU+S[u], W-S[u]));
dp[1][0][u] = max(0ll, max(UU-S[u], W-S[u]));
dp[1][1][u] = max(0ll, max(S[u]+0ll, max(UU-S[u], W-S[u])));
return;
}
signed main()
{
fast();
int n;
cin >> n;
for(int i = 1; i < n; i++)
{
int u, v; cin >> u >> v;
adj[u].pb(v); adj[v].pb(u);
}
for(int i = 1; i <= n; i++)
{
char c; cin >> c;
S[i] = (c=='1');
}
dfs(1, 0);
cout << (max(dp[0][1][1], dp[0][0][1])) << "\n";
return 0;
}
