#include <bits/stdc++.h>
#define F first
#define S second
#define mp make_pair
#define pb push_back
//#define ll __int128
#define ll long long
#define int long long
#define LEFT(a) ((a)<<1)
#define RIGHT(a) (LEFT(a) + 1)
#define MID(a,b) ((a+b)>>1)
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define y1 y122
/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
/*
#pragma GCC optimize ("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2,fma")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC target ("avx2")
#pragma GCC optimization ("unroll-loops")
#pragma comment(linker, "/STACK: 20000000005")
*/
using namespace std;
const int N = 200005;
int n, ans;
int c[N];
int dp[N], DP[N];
vector < int > g[N];
void dfs (int k, int p){
for (int to : g[k]){
if (to == p)
continue;
dfs (to, k);
dp[k] += dp[to];
}
dp[k] = max (dp[k] - c[k], c[k]);
}
void go (int k, int p, int X){
int sum = 0;
ans = max (ans, c[k] + X);
for (int to : g[k]){
if (to == p)
continue;
sum += dp[to];
ans = max (ans, c[k] + dp[to]);
}
sum += X;
ans = max (ans, sum - c[k]);
for (int to : g[k]){
if (to == p)
continue;
sum -= dp[to];
int mx = max (c[k], sum - c[k]);
go (to, k, mx);
sum += dp[to];
}
}
main()
{
//freopen ("in.in", "r", stdin);freopen ("out.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin >> n;
for (int u, v, i = 1; i < n; i++){
cin >> u >> v;
g[u].pb (v);
g[v].pb (u);
}
char ch;
for (int i = 1; i <= n; i++){
cin >> ch;
c[i] = ch - '0';
c[0] += c[i];
}
if (c[0] >= 2)
ans = 2;
else
ans = c[0];
dfs (1, 0);
go (1, 0, 0);
cout << ans << endl;
}
